Postoperative pain is an acute pain that appears due to the surgical act, reaching its maximum intensity in the first 24 - 48 hours after surgery. Postoperative pain control reduces possible postoperative complication...Postoperative pain is an acute pain that appears due to the surgical act, reaching its maximum intensity in the first 24 - 48 hours after surgery. Postoperative pain control reduces possible postoperative complications, as well as the patient’s stay in the medical institution. Objective: This study compared the effectiveness and side effects of oral transmucosal fentanyl citrate (OTFC) with IV morphine in the control of postoperative pain. Methods: Seventy-three patients (Fentanyl group: 27, morphine group: 46) were included. Changes in pain were evaluated with Visual Analog Scale (VAS) and Pain Relief Scale, Pain Intensity Differences (PID), Sum of Pain Intensity Differences (SPID), and Total Pain Relief (TOTPAR). At time zero, 15, 30, 45 min and 1, 2, 3, 4, 5 and 6 h. Results: The decrease in pain intensity measured by VAS was similar in both groups with no significant differences at any of the measurement points. Both products produced a significant increase in the Pain Relief scale, with no differences between groups at any of the measurement times. There were no differences between groups when comparing PID. Comparing SPID between groups, there were no differences at 15, 30 minutes, then there were significant differences in favor of the Fentanyl group up to 6 hours. Both products produced a significant increase in the TOPAR scale, with no differences between groups at any of the measurement times. The appearance of adverse effects was similar in both groups. Conclusions: Both products produced a significant reduction in the measures of pain intensity (VAS), increase of SPID, as well as a significant increase in the Pain Relief scale, a significant increase in the TOPAR scale, with no differences between the groups. The number of adverse effects was similar. The convenience of OTFC administration allows its administration without the special conditions needed for the administration of IV morphine.展开更多
OBJECTIVE:To investigate the mechanism underlying the effect of the Huanglian decoction(黄连汤,HLD)on morphine tolerance(MT),using network pharmacology,and to verify these mechanisms in vitro and in vivo.METHODS:Avail...OBJECTIVE:To investigate the mechanism underlying the effect of the Huanglian decoction(黄连汤,HLD)on morphine tolerance(MT),using network pharmacology,and to verify these mechanisms in vitro and in vivo.METHODS:Available biological data on each drug in the HLD were retrieved from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform.The target proteins of MT were retrieved from the GeneCards,PharmGkb,Therapeutic Target Database,DrugBank,and Online Mendelian Inheritance in Man databases.Information regarding MT and the drug targets was compared to obtain overlapping elements.This information was imported into the Search Tool for the Retrieval of Interacting Genes/Proteins platform to obtain a protein-protein interaction network diagram.Then,a“component-target”network diagram was constructed using screened drug components and target information,via Cytoscape(Institute for Systems Biology,Seattle,WA,USA).The database for annotation,visualization,and integrated discovery was used for Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathways analyses.Pathway information predicted by network pharmacology was verified using animal studies and cell experiments.RESULTS:Network pharmacology analysis identified 22 active compounds of HLD and revealed that HLD partially ameliorated MT by modulating inflammatory,apoptosis,and nuclear factor kappa B(NF-κB)signaling pathways.Berberine(BBR),one of the main components of HLD,inhibited the development of MT in mice.BBR reduced cell viability while increasing B-cell lymphoma 2(Bcl-2)protein expression and decreasing CD86,NF-κB,Bax,and Caspase-3 protein expression in brain vascular 2(BV2)mcroglia cells treated with morphine.Additionally,BBR contributed to a reduction in pro-inflammatory cytokine release and apoptotic cell number.CONCLUSIONS:BBR,a key component of HLD,effectively suppressed microglial activation and neuroinflammation by regulating the NF-κB and apoptosis signaling pathways,thereby delaying MT.This study offers a novel approach to enhance the clinical analgesic efficacy of morphine.展开更多
Objective: Postoperative pain (POP) following abdominal surgery can vary from a few hours to several days. This acute, unrelieved pain can become chronic, requiring patients to take analgesics on an almost daily basis...Objective: Postoperative pain (POP) following abdominal surgery can vary from a few hours to several days. This acute, unrelieved pain can become chronic, requiring patients to take analgesics on an almost daily basis for comfort. Analgesia using general opioids has many side effects and intrathecal morphine is a good alternative. This study was conducted to evaluate the efficacy of intrathecal morphine (ITM) versus conventional analgesia in the management of postoperative pain in colectomy performed by laparoscopic surgery. Methods: Cohort study conducted at the Hôpital Nord in Marseille, from 01 January to 31 July 2021 in patients aged at least 18 years undergoing anaesthesia for scheduled colectomy by laparoscopic surgery. The primary endpoint was postoperative pain intensity and the secondary endpoints were morphine consumption, treatment side effects and length of hospital stay. Statistical analysis was performed using XLSTAT software. Results: We included 193 patients: 131 in the control group (conventional analgesia) and 62 in the ITM group. We observed: a significant decrease in pain (assessed by numerical scale) in favour of the ITM group in the post-anaesthetic care room, i.e. 3 (±4) vs 1 (±2), p 0 and H2: 2 (±2) vs. 1 (±2);p Conclusion: These results suggest that intrathecal morphine (ITM) in laparoscopic colectomy provides effective postoperative analgesia with low morphine consumption, and a reduction in morphine side-effects compared with conventional analgesia.展开更多
Background: Neuraxial anesthesia with intrathecal morphine is the reference technique in cesarean section anesthesia for the management of postoperative analgesia. If there is a contraindication to this, general anest...Background: Neuraxial anesthesia with intrathecal morphine is the reference technique in cesarean section anesthesia for the management of postoperative analgesia. If there is a contraindication to this, general anesthesia is required. The objective of the study was to evaluate the analgesic effectiveness of 4 analgesic techniques performed during cesarean section under general anesthesia in two centers with different anesthetic practices (North Franche Comté Hospital and Omar Bongo Ondimba Army Training Hospital). Method: This is a retrospective and descriptive study over 2 years, from January 1, 2019 to December 31, 2020. It involved evaluating the analgesic effectiveness and tolerance of morphine in the epidural catheter, wound infiltration, intravenous analgesia and Transversus Abdominous Plane block (TAP block) from the post-anesthesia care unit (PACU) until the 4<sup>th</sup> post-operative day. Results: Of the 354 cesarean sections performed, 84 (11.14%) received general anesthesia. The average age was 32.27 years. Acute fetal distress was the first indication for cesarean section (45.2%), followed by hemorrhagic placenta previa (10.7%) and prolapse of the cord (8.33%). Morphine in the epidural catheter was the most used (47.6%) followed by parietal infiltration (36.9%), intravenous analgesia (13.1%) and TAP block (2.38%). The analgesic effectiveness was comparable between the techniques from postoperative day 0 to day 4. No difference in side effects. Postoperative morphine consumption was significantly reduced (p = 0.011) in the infiltration (9 mg) and TAP block (9mg) groups compared to the epidural catheter (16 mg) and intravenous analgesia (17 mg). No difference in 02 rehabilitation criteria (ambulation, first bowel movement). No difference in the occurrence of chronic pain. Conclusion: In the event of a cesarean section under general anesthesia, there are effective and well-tolerated alternatives to neuraxial anesthesia, particularly regional anesthesia techniques (nerve blocks), particularly in countries with low availability of morphine.展开更多
Objective:This research utilizes the FAERS for data mining to identify heart-related side effects caused by opioids,ensuring the safe use of these medications.Methods:Data from 79 quarters(Q12004 to Q32023)involving a...Objective:This research utilizes the FAERS for data mining to identify heart-related side effects caused by opioids,ensuring the safe use of these medications.Methods:Data from 79 quarters(Q12004 to Q32023)involving adverse event(AE)reports for opioids like morphine and oxycodone was reviewed.We applied the MedDRA system to categorize events and used statistical tools,ROR and BCPNN,for signal detection.These findings were cross-checked with drug labels and SIDER 4.1 for accuracy.Identified risks were then categorized by severity using DME and IME classifications.Results:Analysis of adverse events(AEs)for the five examined drugs(35359,14367,144441,10592,and 28848)identified 33,6,12,37,and 34 cardiovascular AEs,and 16,5,7,25,and 21 instances of important medical events(IMEs)respectively.Each drug was linked to cases of cardiac and cardiopulmonary arrest.The cardiovascular AEs varied widely in occurrence and severity,with methadone notably presenting diverse and potent risks,including sudden cardiac death as a distinct medical event(DME).A comparison with SIDER 4.1 showed 11 opioid-related cardiovascular AEs in line with our findings.Standardized MedDRA Queries(SMQs)confirmed these results,indicating stronger signals for methadone and tramadol,while morphine,hydromorphone,and oxycodone exhibited fewer and weaker signals.Conclusion:The study revealed numerous heart-related adverse effects(AEs)not listed on drug labels and identified new AE patterns.Recognizing these differences in AE profiles and risks across different opioids is crucial for safer prescription practices to minimize cardiac complications.展开更多
Introduction: Ambulatory surgery requires effective analgesia with few side effects to allow a return home on the day of surgery. The aim of the study was to compare the efficacy of intrathecal morphine (Ram) and erec...Introduction: Ambulatory surgery requires effective analgesia with few side effects to allow a return home on the day of surgery. The aim of the study was to compare the efficacy of intrathecal morphine (Ram) and erector spinae plane block (ESP) in outpatient abdominal wall surgery. Methodology: Thirty-six patients were randomized into two groups. The ESP group (n = 23) benefited from the ESP block with bupivacaine 5% (20 ml) followed by spinal anesthesia with bupivacaine (7.5 mg) and sufenta (2.5 µg). The Ram group (n = 13) benefited from spinal anesthesia with bupivacaine (7.5 mg), sufenta (2.5 µg) and morphine (100 µg). The primary endpoint was whether or not to return home on the day of surgery. The secondary endpoint was the pain score by the visual analog scale (VAS) in the post-intervention monitoring room (SSPI). After 2 hours (H2) and one day (D1) after surgery, the morphine consumption in the immediate postoperative period (mg) and the undesirable effects. Results: Inguinal hernia surgery predominated (n = 30). No difference in age (45.05 vs 50.7;p = 0.4), ASA score (1.43 vs 1.53;p = 0.57). All patients (n = 36) returned home on the day of surgery. No difference in postoperative pain in SSPI (p = 0.6), 2 hours after surgery (p = 0.40) and the day after surgery (p = 0.6). Postoperative morphine consumption was identical (0.9 mg vs 0.2 mg, p = 0.2). There were 2 urinary retentions in the Ram group. Conclusion: The erector spinae plane block and intrathecal morphine are well tolerated and perfectly compatible with the requirements of outpatient abdominal wall surgery.展开更多
To investigate the involvement of central serotonergic system in behavioral sensitization to morphine in mice. Male Kunming mice were treated （i.p.） with saline or morphine 10 mg/kg twice daily for 3 d and then drug...To investigate the involvement of central serotonergic system in behavioral sensitization to morphine in mice. Male Kunming mice were treated （i.p.） with saline or morphine 10 mg/kg twice daily for 3 d and then drug manipulation was suspended for 5 d. On day 9, a challenge dose of morphine （10 mg/kg） was given and the locomotor activity was measured for 60 rain to confkrm the establishment of behavioral sensitization in mice. Moreover, 5-hydroxytryptophan （5-HTP）, a precursor of serotonin, at the doses of 20-80 mg/kg was given i.p. in combination with daily morphine treatment （induction）, during the morphine treatment suspension （transfer） or prior to the challenge dose of morphine （expression） and locomotor activity was measured on day 9 after the challenge dose of morphine. Twice daily of morphine injection induced robust behavioral sensitization in mice as evidenced by significantly higher locomotion on day 9 for multiple treatment with morphine than saline in mice. 5-HTP treatment selec- tively and dose-dependently blocked the induction, but not the transfer nor the expression of morphine induced behavioral sensitization. This study provides clear evidence that up-regulation of central serotonergic system may suppress the induction of morphine sensitization in mice.展开更多
Objective To investigate the influence of dopamine （DA） and DA receptor＇s antagonist on the transmission of noxious information in the central nervous system of normal rats or morphinistic rats. Methods The influen...Objective To investigate the influence of dopamine （DA） and DA receptor＇s antagonist on the transmission of noxious information in the central nervous system of normal rats or morphinistic rats. Methods The influence of DA on the electric activity of the pain-excited neuron （PEN） in the caudate nucleus （Cd） of normal rats or morphinistic rats was recorded after the sciatic nerve was noxiously stimulated. Results DA shortened the average latency of the evoked discharge of PEN in the Cd of normal rats, indicating that DA could increase the activity of PEN and pain sensitivity in normal rats. This effect could be inhibited by Droperidol. DA increased the average latency of the evoked discharge of PEN in the Cd of morphinistic rats, indicating that DA could inhibit the activity of PEN and pain sensitivity in morphinistic rats. Conclusion The responses to painful stimulation were completely opposite between normal rats and morphinistic rats after the intracerebroventricular injection of DA.展开更多
文摘Postoperative pain is an acute pain that appears due to the surgical act, reaching its maximum intensity in the first 24 - 48 hours after surgery. Postoperative pain control reduces possible postoperative complications, as well as the patient’s stay in the medical institution. Objective: This study compared the effectiveness and side effects of oral transmucosal fentanyl citrate (OTFC) with IV morphine in the control of postoperative pain. Methods: Seventy-three patients (Fentanyl group: 27, morphine group: 46) were included. Changes in pain were evaluated with Visual Analog Scale (VAS) and Pain Relief Scale, Pain Intensity Differences (PID), Sum of Pain Intensity Differences (SPID), and Total Pain Relief (TOTPAR). At time zero, 15, 30, 45 min and 1, 2, 3, 4, 5 and 6 h. Results: The decrease in pain intensity measured by VAS was similar in both groups with no significant differences at any of the measurement points. Both products produced a significant increase in the Pain Relief scale, with no differences between groups at any of the measurement times. There were no differences between groups when comparing PID. Comparing SPID between groups, there were no differences at 15, 30 minutes, then there were significant differences in favor of the Fentanyl group up to 6 hours. Both products produced a significant increase in the TOPAR scale, with no differences between groups at any of the measurement times. The appearance of adverse effects was similar in both groups. Conclusions: Both products produced a significant reduction in the measures of pain intensity (VAS), increase of SPID, as well as a significant increase in the Pain Relief scale, a significant increase in the TOPAR scale, with no differences between the groups. The number of adverse effects was similar. The convenience of OTFC administration allows its administration without the special conditions needed for the administration of IV morphine.
基金Natural Science Foundation-funded Project:Study on the Mechanism of Mechanical Stress Sensing Element Piezo Type Mechanosensitive Ion Channel Component 2 Interacting with Nuclear Receptor Subfamily 4 Group A Member 2 Mediating Traumatic Brain Injury(No.82172190)。
文摘OBJECTIVE:To investigate the mechanism underlying the effect of the Huanglian decoction(黄连汤,HLD)on morphine tolerance(MT),using network pharmacology,and to verify these mechanisms in vitro and in vivo.METHODS:Available biological data on each drug in the HLD were retrieved from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform.The target proteins of MT were retrieved from the GeneCards,PharmGkb,Therapeutic Target Database,DrugBank,and Online Mendelian Inheritance in Man databases.Information regarding MT and the drug targets was compared to obtain overlapping elements.This information was imported into the Search Tool for the Retrieval of Interacting Genes/Proteins platform to obtain a protein-protein interaction network diagram.Then,a“component-target”network diagram was constructed using screened drug components and target information,via Cytoscape(Institute for Systems Biology,Seattle,WA,USA).The database for annotation,visualization,and integrated discovery was used for Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathways analyses.Pathway information predicted by network pharmacology was verified using animal studies and cell experiments.RESULTS:Network pharmacology analysis identified 22 active compounds of HLD and revealed that HLD partially ameliorated MT by modulating inflammatory,apoptosis,and nuclear factor kappa B(NF-κB)signaling pathways.Berberine(BBR),one of the main components of HLD,inhibited the development of MT in mice.BBR reduced cell viability while increasing B-cell lymphoma 2(Bcl-2)protein expression and decreasing CD86,NF-κB,Bax,and Caspase-3 protein expression in brain vascular 2(BV2)mcroglia cells treated with morphine.Additionally,BBR contributed to a reduction in pro-inflammatory cytokine release and apoptotic cell number.CONCLUSIONS:BBR,a key component of HLD,effectively suppressed microglial activation and neuroinflammation by regulating the NF-κB and apoptosis signaling pathways,thereby delaying MT.This study offers a novel approach to enhance the clinical analgesic efficacy of morphine.
文摘Objective: Postoperative pain (POP) following abdominal surgery can vary from a few hours to several days. This acute, unrelieved pain can become chronic, requiring patients to take analgesics on an almost daily basis for comfort. Analgesia using general opioids has many side effects and intrathecal morphine is a good alternative. This study was conducted to evaluate the efficacy of intrathecal morphine (ITM) versus conventional analgesia in the management of postoperative pain in colectomy performed by laparoscopic surgery. Methods: Cohort study conducted at the Hôpital Nord in Marseille, from 01 January to 31 July 2021 in patients aged at least 18 years undergoing anaesthesia for scheduled colectomy by laparoscopic surgery. The primary endpoint was postoperative pain intensity and the secondary endpoints were morphine consumption, treatment side effects and length of hospital stay. Statistical analysis was performed using XLSTAT software. Results: We included 193 patients: 131 in the control group (conventional analgesia) and 62 in the ITM group. We observed: a significant decrease in pain (assessed by numerical scale) in favour of the ITM group in the post-anaesthetic care room, i.e. 3 (±4) vs 1 (±2), p 0 and H2: 2 (±2) vs. 1 (±2);p Conclusion: These results suggest that intrathecal morphine (ITM) in laparoscopic colectomy provides effective postoperative analgesia with low morphine consumption, and a reduction in morphine side-effects compared with conventional analgesia.
文摘Background: Neuraxial anesthesia with intrathecal morphine is the reference technique in cesarean section anesthesia for the management of postoperative analgesia. If there is a contraindication to this, general anesthesia is required. The objective of the study was to evaluate the analgesic effectiveness of 4 analgesic techniques performed during cesarean section under general anesthesia in two centers with different anesthetic practices (North Franche Comté Hospital and Omar Bongo Ondimba Army Training Hospital). Method: This is a retrospective and descriptive study over 2 years, from January 1, 2019 to December 31, 2020. It involved evaluating the analgesic effectiveness and tolerance of morphine in the epidural catheter, wound infiltration, intravenous analgesia and Transversus Abdominous Plane block (TAP block) from the post-anesthesia care unit (PACU) until the 4<sup>th</sup> post-operative day. Results: Of the 354 cesarean sections performed, 84 (11.14%) received general anesthesia. The average age was 32.27 years. Acute fetal distress was the first indication for cesarean section (45.2%), followed by hemorrhagic placenta previa (10.7%) and prolapse of the cord (8.33%). Morphine in the epidural catheter was the most used (47.6%) followed by parietal infiltration (36.9%), intravenous analgesia (13.1%) and TAP block (2.38%). The analgesic effectiveness was comparable between the techniques from postoperative day 0 to day 4. No difference in side effects. Postoperative morphine consumption was significantly reduced (p = 0.011) in the infiltration (9 mg) and TAP block (9mg) groups compared to the epidural catheter (16 mg) and intravenous analgesia (17 mg). No difference in 02 rehabilitation criteria (ambulation, first bowel movement). No difference in the occurrence of chronic pain. Conclusion: In the event of a cesarean section under general anesthesia, there are effective and well-tolerated alternatives to neuraxial anesthesia, particularly regional anesthesia techniques (nerve blocks), particularly in countries with low availability of morphine.
文摘Objective:This research utilizes the FAERS for data mining to identify heart-related side effects caused by opioids,ensuring the safe use of these medications.Methods:Data from 79 quarters(Q12004 to Q32023)involving adverse event(AE)reports for opioids like morphine and oxycodone was reviewed.We applied the MedDRA system to categorize events and used statistical tools,ROR and BCPNN,for signal detection.These findings were cross-checked with drug labels and SIDER 4.1 for accuracy.Identified risks were then categorized by severity using DME and IME classifications.Results:Analysis of adverse events(AEs)for the five examined drugs(35359,14367,144441,10592,and 28848)identified 33,6,12,37,and 34 cardiovascular AEs,and 16,5,7,25,and 21 instances of important medical events(IMEs)respectively.Each drug was linked to cases of cardiac and cardiopulmonary arrest.The cardiovascular AEs varied widely in occurrence and severity,with methadone notably presenting diverse and potent risks,including sudden cardiac death as a distinct medical event(DME).A comparison with SIDER 4.1 showed 11 opioid-related cardiovascular AEs in line with our findings.Standardized MedDRA Queries(SMQs)confirmed these results,indicating stronger signals for methadone and tramadol,while morphine,hydromorphone,and oxycodone exhibited fewer and weaker signals.Conclusion:The study revealed numerous heart-related adverse effects(AEs)not listed on drug labels and identified new AE patterns.Recognizing these differences in AE profiles and risks across different opioids is crucial for safer prescription practices to minimize cardiac complications.
文摘Introduction: Ambulatory surgery requires effective analgesia with few side effects to allow a return home on the day of surgery. The aim of the study was to compare the efficacy of intrathecal morphine (Ram) and erector spinae plane block (ESP) in outpatient abdominal wall surgery. Methodology: Thirty-six patients were randomized into two groups. The ESP group (n = 23) benefited from the ESP block with bupivacaine 5% (20 ml) followed by spinal anesthesia with bupivacaine (7.5 mg) and sufenta (2.5 µg). The Ram group (n = 13) benefited from spinal anesthesia with bupivacaine (7.5 mg), sufenta (2.5 µg) and morphine (100 µg). The primary endpoint was whether or not to return home on the day of surgery. The secondary endpoint was the pain score by the visual analog scale (VAS) in the post-intervention monitoring room (SSPI). After 2 hours (H2) and one day (D1) after surgery, the morphine consumption in the immediate postoperative period (mg) and the undesirable effects. Results: Inguinal hernia surgery predominated (n = 30). No difference in age (45.05 vs 50.7;p = 0.4), ASA score (1.43 vs 1.53;p = 0.57). All patients (n = 36) returned home on the day of surgery. No difference in postoperative pain in SSPI (p = 0.6), 2 hours after surgery (p = 0.40) and the day after surgery (p = 0.6). Postoperative morphine consumption was identical (0.9 mg vs 0.2 mg, p = 0.2). There were 2 urinary retentions in the Ram group. Conclusion: The erector spinae plane block and intrathecal morphine are well tolerated and perfectly compatible with the requirements of outpatient abdominal wall surgery.
基金Supported by the Key Research and Development Plan of Shandong Province(2018GGX106001)supported by the Natural Science Foundation of Shandong Province(ZR2017MEE066)Supported by the Science and Technology Plan of Shandong higher Education institutions(J16LB58)~~
基金National Natural Science Foundation of China (Grant No. 30570653)National Basic Research Program of China (Grant No. 2003CB515400)985 Program of China Ministry of Education
文摘To investigate the involvement of central serotonergic system in behavioral sensitization to morphine in mice. Male Kunming mice were treated （i.p.） with saline or morphine 10 mg/kg twice daily for 3 d and then drug manipulation was suspended for 5 d. On day 9, a challenge dose of morphine （10 mg/kg） was given and the locomotor activity was measured for 60 rain to confkrm the establishment of behavioral sensitization in mice. Moreover, 5-hydroxytryptophan （5-HTP）, a precursor of serotonin, at the doses of 20-80 mg/kg was given i.p. in combination with daily morphine treatment （induction）, during the morphine treatment suspension （transfer） or prior to the challenge dose of morphine （expression） and locomotor activity was measured on day 9 after the challenge dose of morphine. Twice daily of morphine injection induced robust behavioral sensitization in mice as evidenced by significantly higher locomotion on day 9 for multiple treatment with morphine than saline in mice. 5-HTP treatment selec- tively and dose-dependently blocked the induction, but not the transfer nor the expression of morphine induced behavioral sensitization. This study provides clear evidence that up-regulation of central serotonergic system may suppress the induction of morphine sensitization in mice.
文摘Objective To investigate the influence of dopamine （DA） and DA receptor＇s antagonist on the transmission of noxious information in the central nervous system of normal rats or morphinistic rats. Methods The influence of DA on the electric activity of the pain-excited neuron （PEN） in the caudate nucleus （Cd） of normal rats or morphinistic rats was recorded after the sciatic nerve was noxiously stimulated. Results DA shortened the average latency of the evoked discharge of PEN in the Cd of normal rats, indicating that DA could increase the activity of PEN and pain sensitivity in normal rats. This effect could be inhibited by Droperidol. DA increased the average latency of the evoked discharge of PEN in the Cd of morphinistic rats, indicating that DA could inhibit the activity of PEN and pain sensitivity in morphinistic rats. Conclusion The responses to painful stimulation were completely opposite between normal rats and morphinistic rats after the intracerebroventricular injection of DA.
