Inhibition of medullary raphé/parapyramidal neurons prevents cutaneous vasoconstriction elicited by alerting stimuli and by cold exposure in conscious rabbits.
In conscious rabbits, microinjection of muscimol into the medullary raphé/parapyramidal region decreased fluctuation (coefficient variation) of resting ear blood flow (from 62 +/- 8 to 25 +/- 4%, P < 0.01, n = 8). The muscimol injection also prevented falls in ear blood flow that normally occur in response to alerting stimuli and to cold exposure. Thus, raphé/parapyramidal neurons constitute an important brainstem center for mediating cutaneous vasoconstriction initiated by alerting stimuli and by cold exposure.
Department of Human Physiology, Centre for Neuroscience, Flinders University, Bedford Park, South Australia 5042, Australia. yoichiro.otsuka@flinders.edu.au
Youichirou
Y
Ootsuka
William W
WW
Blessing
D000818:Animals; D001143:Arousal / Q000187:drug effects / Q000502:physiology; D001833:Body Temperature Regulation / Q000187:drug effects / Q000502:physiology; D003080:Cold Temperature; D004423:Ear / Q000098:blood supply; D018755:GABA Agonists / Q000008:administration & dosage*; D008297:Male; D008845:Microinjections; D009118:Muscimol / Q000008:administration & dosage*; D017966:Pyramidal Cells / Q000187:drug effects* / Q000502:physiology; D011817:Rabbits; D011903:Raphe Nuclei / Q000187:drug effects* / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology
D018755:GABA Agonists; D009118:Muscimol