Aggression is a common behavioral strategy employed by animals to secure limited resources, but must be applied with restraint to limit potential costs including injury. How animals make the adap- tive decision to fig...Aggression is a common behavioral strategy employed by animals to secure limited resources, but must be applied with restraint to limit potential costs including injury. How animals make the adap- tive decision to fight or flee is barely known. Here, we review our work on crickets that reveals the roles of biogenic amines, primarily octopamine （the insect analog of noradrenaline） and nitric oxide （NO）. Using aminergic drugs, we found that amines are not essential for actually initiating aggres- sion. However, octopamine is necessary for mediating the aggression-promoting effects of poten- tially rewarding experiences including stimulation with a male antenna, physical exertion, winning, and resource possession. Hence, octopamine can be considered as the motivational component of aggression. Imposed handicaps that impede aggressive signaling revealed that the agonistic actions of an opponent perceived during fighting act to reduce aggression, and that crickets make the deci- sion to flee the moment the accumulated sum of such aversive experiences exceeds some critical level. Treatment with nitridergic drugs revealed that the impact of the opponent＇s aggressive actions is mediated by NO. NO acts to suppress aggression by promoting the tendency to flee and is primarily responsible for the depressed aggressiveness of subordinates after social defeat. Octopamine and dopamine can each restore aggression in subordinates, but only dopamine is necessary for normal recovery. The role of serotonin remains unclear, and is discussed. We conclude that octopamine and NO control the decision to fight or flee by mediating the effects of potentially rewarding and aversive experiences, respectively.展开更多
Our recent findings have demonstrated that rodent models of closed head traumatic brain injury exhibit comprehensive evidence of progressive and enduring orofacial allodynias,a hypersensitive pain response induced by ...Our recent findings have demonstrated that rodent models of closed head traumatic brain injury exhibit comprehensive evidence of progressive and enduring orofacial allodynias,a hypersensitive pain response induced by non-painful stimulation.These allodynias,tested using thermal hyperalgesia,correlated with changes in several known pain signaling receptors and molecules along the trigeminal pain pathway,especially in the trigeminal nucleus caudalis.This study focused to extend our previous work to investigate the changes in monoamine neurotransmitter immunoreactivity changes in spinal trigeminal nucleus oralis,pars interpolaris and nucleus tractus solitaries following mild to moderate closed head traumatic brain injury,which are related to tactile allodynia,touch-pressure sensitivity,and visceral pain.Our results exhibited significant alterations in the excitatory monoamine,serotonin,in spinal trigeminal nucleus oralis and pars interpolaris which usually modulate tactile and mechanical sensitivity in addition to the thermal sensitivity.Moreover,we also detected a robust alteration in the expression of serotonin,and inhibitory molecule norepinephrine in the nucleus tractus solitaries,which might indicate the possibility of an alteration in visceral pain,and existence of other morbidities related to solitary nucleus dysfunction in this rodent model of mild to moderate closed head traumatic brain injury.Collectively,widespread changes in monoamine neurotransmitter may be related to orofacial allodynhias and headache after traumatic brain injury.展开更多
文摘Aggression is a common behavioral strategy employed by animals to secure limited resources, but must be applied with restraint to limit potential costs including injury. How animals make the adap- tive decision to fight or flee is barely known. Here, we review our work on crickets that reveals the roles of biogenic amines, primarily octopamine （the insect analog of noradrenaline） and nitric oxide （NO）. Using aminergic drugs, we found that amines are not essential for actually initiating aggres- sion. However, octopamine is necessary for mediating the aggression-promoting effects of poten- tially rewarding experiences including stimulation with a male antenna, physical exertion, winning, and resource possession. Hence, octopamine can be considered as the motivational component of aggression. Imposed handicaps that impede aggressive signaling revealed that the agonistic actions of an opponent perceived during fighting act to reduce aggression, and that crickets make the deci- sion to flee the moment the accumulated sum of such aversive experiences exceeds some critical level. Treatment with nitridergic drugs revealed that the impact of the opponent＇s aggressive actions is mediated by NO. NO acts to suppress aggression by promoting the tendency to flee and is primarily responsible for the depressed aggressiveness of subordinates after social defeat. Octopamine and dopamine can each restore aggression in subordinates, but only dopamine is necessary for normal recovery. The role of serotonin remains unclear, and is discussed. We conclude that octopamine and NO control the decision to fight or flee by mediating the effects of potentially rewarding and aversive experiences, respectively.
基金supported by Merit Review Awards(No.B6570R,B78071,and B1005-R)from the United States(U.S.)Department of Veterans Affairs Rehabilitation Research and Development Service
文摘Our recent findings have demonstrated that rodent models of closed head traumatic brain injury exhibit comprehensive evidence of progressive and enduring orofacial allodynias,a hypersensitive pain response induced by non-painful stimulation.These allodynias,tested using thermal hyperalgesia,correlated with changes in several known pain signaling receptors and molecules along the trigeminal pain pathway,especially in the trigeminal nucleus caudalis.This study focused to extend our previous work to investigate the changes in monoamine neurotransmitter immunoreactivity changes in spinal trigeminal nucleus oralis,pars interpolaris and nucleus tractus solitaries following mild to moderate closed head traumatic brain injury,which are related to tactile allodynia,touch-pressure sensitivity,and visceral pain.Our results exhibited significant alterations in the excitatory monoamine,serotonin,in spinal trigeminal nucleus oralis and pars interpolaris which usually modulate tactile and mechanical sensitivity in addition to the thermal sensitivity.Moreover,we also detected a robust alteration in the expression of serotonin,and inhibitory molecule norepinephrine in the nucleus tractus solitaries,which might indicate the possibility of an alteration in visceral pain,and existence of other morbidities related to solitary nucleus dysfunction in this rodent model of mild to moderate closed head traumatic brain injury.Collectively,widespread changes in monoamine neurotransmitter may be related to orofacial allodynhias and headache after traumatic brain injury.
