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.
Ootsuka
Youichirou
Y
Department of Human Physiology, Centre for Neuroscience, Flinders University, Bedford Park, South Australia 5042, Australia. yoichiro.otsuka@flinders.edu.au
Blessing
William W
WW
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