Thermally induced peripheral blood flow changes in chickens.
Changes in wattle blood flow (Q) and vascular resistance (R) were examined during both local heating of the wattle and/or general body heating of unanesthetized, male White Leghorn chickens. Q increased and R decreased during both local and general heating. Termination of heating reversed the response. Beta stimulation with isoproterenol markedly reduced R and increased Q in normothermic birds, suggesting the presence of beta receptors in the wattle vasculature. Alpha blockade with phenoxybenzamine also resulted in pronounced vasodilatation, suggesting tonic alpha-sympathetic tone in the wattle vasculature under normothermic conditions. Neither cholinergic blockade with atropine sulfate nor beta-adrenergic blockade with propranolol altered the vascular response to general heating when administered near its peak. Release of alpha-sympathetic tone is believed to subserve the response to general heating.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001833:Body Temperature Regulation; D002645:Chickens / Q000502:physiology*; D003129:Comb and Wattles / Q000098:blood supply*; D006358:Hot Temperature; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010643:Phenoxybenzamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D010643:Phenoxybenzamine; D001285:Atropine; D011433:Propranolol; D007545:Isoproterenol; D000109:Acetylcholine