Objective: To study the characteristics of the postsynaptic potentials in thoracic sympatheticpreganglionic neurons (SPNs) evoked by electrical stimulation of the rostral ventrolateral medulla (RVLM ) incats. Methods:...Objective: To study the characteristics of the postsynaptic potentials in thoracic sympatheticpreganglionic neurons (SPNs) evoked by electrical stimulation of the rostral ventrolateral medulla (RVLM ) incats. Methods: In 11 α--chloralose/urethane anesthetized, artificially ventilated cats, intracellular recordings weremade from T, spinal cord with microelectrodes filled with 3 mol/L KCl. SPNs were identified by antidromicstimulation of the T3 white ramus. Results: Twenty--four SPNs were recorded, the resting membrane potentials ofwhich ranged between -- 45 -- -- 90 mV. The onset latency and threshold of the antidromic action potentialsaveraged (6. 48 + 0. 89) ms and (2. 86 + 0. 37) V respectively. Single pulse (0. 2 ms. 50-- 300 PA) electricalstimulation of RVLM evoked fast excitatory postsynaptic potentials (eEPSPs) with short latencies (4--47 ms) inall the 24 SPNs. In 11 of the SPNs, EPSPs with longer latencies (IEPSPs, 70-- 140 ms) were also recorded. Mostof the eEPSPs and some of the IEPSPs were typical monosynaptic EPSPs as they were of constant onset latency.Conclusion: The results provided direct physiological evidence for that some RVLM sympathoexcitatory neuronsproject monosynaptically to thoracic SPNs. The descending pathways from RVLM may consist of two distinctgroups of fibers, the conduction velocities were calculated to be 5--25 m/s and 0. 78-- 1. 6 m/s respectively.展开更多
The cytogrchitecture and dendroarchitecture of sympathoadrenal preganglionic neurons (SAPN) that innervate the adrenal medulla have been studied in adult rats. Retrograde transport of choleragen subunit B horseradish ...The cytogrchitecture and dendroarchitecture of sympathoadrenal preganglionic neurons (SAPN) that innervate the adrenal medulla have been studied in adult rats. Retrograde transport of choleragen subunit B horseradish peroxidase conjugate (GB-HRP) injetted into the left adrenal medulla resulted in the labelling of SAPN in the ipsilateral intermediate zone from T1 to L1 segments. Four subnuclei of SAPN were distinguished and located in ILP, ILF, IC and ICPe of the spinal cord respectively. The dendritic trees of neurons in ILP exhibited dendritic patterns with extension oriented longitudinally and mediolaterally. The present findings provide detailed descriptions of the somatic structure and accompanying dendritic trees of SAPN. The observations also include anatomical evidence that two systems of circuits may exist in regulating the actiVities of SAPN; one is the classic core circuits system which mainly received the inputs from fibers in parallel direction with longitudinal dendrites in ILP and the other is the paralateral circuits system which chiefly received the inputs from fibers iu perpeudicular direction with radial dendrites in white matter.展开更多
When faced with danger,pufferfish react with both a fast-start escape response and inflation behavior.The neural basis of these stress responses in the pufferfish has not been described.The present study reveals that ...When faced with danger,pufferfish react with both a fast-start escape response and inflation behavior.The neural basis of these stress responses in the pufferfish has not been described.The present study reveals that during inflation behavior,the buccal cavity expands and compresses as a pump to control the direction of water flow and draws water in and out.The inflation involves a series of major anatomical modifications of the head.The greatly enlarged first branchiostegal ray and its associated hyohyoideus abductor muscle are the key mechanisms responsible for this behavior.The nerve branch innervating the hyohyoideus abductor muscle is highly developed,and its central origin at the motor nucleus of the VIIth cranial nerve was revealed by tract-tracing using the carbocyanine dye DiI.The central connections from its origin were found to be several motor nuclei in the medulla and the spinal cord,the nuclei of cranial nerve III and IV in the mesencephalon,and the pretectalis superficialis and periventricular preoptic nuclei in the diencephalon.Both the sympathetic cells and the parvocellular part of the periventricular preoptic nucleus might play a neuro-endocrine role in the rapid movement of the buccal cavity during puffing behavior in this species of pufferfish.The central circuit revealed by this study is hypothesized to mediate the C-start escape behavior and puffing behavior.展开更多
文摘Objective: To study the characteristics of the postsynaptic potentials in thoracic sympatheticpreganglionic neurons (SPNs) evoked by electrical stimulation of the rostral ventrolateral medulla (RVLM ) incats. Methods: In 11 α--chloralose/urethane anesthetized, artificially ventilated cats, intracellular recordings weremade from T, spinal cord with microelectrodes filled with 3 mol/L KCl. SPNs were identified by antidromicstimulation of the T3 white ramus. Results: Twenty--four SPNs were recorded, the resting membrane potentials ofwhich ranged between -- 45 -- -- 90 mV. The onset latency and threshold of the antidromic action potentialsaveraged (6. 48 + 0. 89) ms and (2. 86 + 0. 37) V respectively. Single pulse (0. 2 ms. 50-- 300 PA) electricalstimulation of RVLM evoked fast excitatory postsynaptic potentials (eEPSPs) with short latencies (4--47 ms) inall the 24 SPNs. In 11 of the SPNs, EPSPs with longer latencies (IEPSPs, 70-- 140 ms) were also recorded. Mostof the eEPSPs and some of the IEPSPs were typical monosynaptic EPSPs as they were of constant onset latency.Conclusion: The results provided direct physiological evidence for that some RVLM sympathoexcitatory neuronsproject monosynaptically to thoracic SPNs. The descending pathways from RVLM may consist of two distinctgroups of fibers, the conduction velocities were calculated to be 5--25 m/s and 0. 78-- 1. 6 m/s respectively.
基金Project supported by the National Natural Science Foundation of China.
文摘The cytogrchitecture and dendroarchitecture of sympathoadrenal preganglionic neurons (SAPN) that innervate the adrenal medulla have been studied in adult rats. Retrograde transport of choleragen subunit B horseradish peroxidase conjugate (GB-HRP) injetted into the left adrenal medulla resulted in the labelling of SAPN in the ipsilateral intermediate zone from T1 to L1 segments. Four subnuclei of SAPN were distinguished and located in ILP, ILF, IC and ICPe of the spinal cord respectively. The dendritic trees of neurons in ILP exhibited dendritic patterns with extension oriented longitudinally and mediolaterally. The present findings provide detailed descriptions of the somatic structure and accompanying dendritic trees of SAPN. The observations also include anatomical evidence that two systems of circuits may exist in regulating the actiVities of SAPN; one is the classic core circuits system which mainly received the inputs from fibers in parallel direction with longitudinal dendrites in ILP and the other is the paralateral circuits system which chiefly received the inputs from fibers iu perpeudicular direction with radial dendrites in white matter.
基金supported by the National Natural Science Foundation of China(No.30970365).
文摘When faced with danger,pufferfish react with both a fast-start escape response and inflation behavior.The neural basis of these stress responses in the pufferfish has not been described.The present study reveals that during inflation behavior,the buccal cavity expands and compresses as a pump to control the direction of water flow and draws water in and out.The inflation involves a series of major anatomical modifications of the head.The greatly enlarged first branchiostegal ray and its associated hyohyoideus abductor muscle are the key mechanisms responsible for this behavior.The nerve branch innervating the hyohyoideus abductor muscle is highly developed,and its central origin at the motor nucleus of the VIIth cranial nerve was revealed by tract-tracing using the carbocyanine dye DiI.The central connections from its origin were found to be several motor nuclei in the medulla and the spinal cord,the nuclei of cranial nerve III and IV in the mesencephalon,and the pretectalis superficialis and periventricular preoptic nuclei in the diencephalon.Both the sympathetic cells and the parvocellular part of the periventricular preoptic nucleus might play a neuro-endocrine role in the rapid movement of the buccal cavity during puffing behavior in this species of pufferfish.The central circuit revealed by this study is hypothesized to mediate the C-start escape behavior and puffing behavior.
