title: Vascular response of the chicken hindlimb to vasoactive agents, asphyxia, and exercise.
abstract: Previous studies in live chickens have measured heart rate, blood pressure, and cardiac output during drug administration or asphyxia and made assumptions concerning the peripheral vasculature. The present study employs a constant-flow, isolated hindlimb perfusion technique to measure directly changes in skeletal muscle vascular resistance induced either by local intra-arterial (i.a.) bolus, or continuous i.a. infusion, of various vasoactive substances. Prostaglandin E1 (0.5 microgram, bolus) produced arteriolar vasodilation lasting 10 min, as indicated by a fall ian perfusion pressure. Bolus injection of histamine (10 microgram diphosphate) or adenosine (5 and 10 microgram) produced vasodilation of less than 2-min duration. Theophylline infusion (5 microM infused at 1 mL/min, i.a.) blocked the effect of adenosine. Norepinephrine (1 microgram) produced vasoconstriction which was reduced 60% by systemic alpha-adrenergic blockade with phenoxybenzamine (7.5-10 mg/kg). Tracheal occlusion produced intense vasoconstriction which was reduced 70% by alpha-adrenergic blockade. Electrical stimulation of the peripheral end of the cut sciatic nerve (6 Hz) produced an immediate vasodilation lasting several minutes.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D002645:Chickens / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D006632:Histamine / Q000494:pharmacology; D008297:Male; D009132:Muscles / Q000098:blood supply*; D009638:Norepinephrine / Q000494:pharmacology; D010477:Perfusion; D010643:Phenoxybenzamine / Q000494:pharmacology; D005082:Physical Exertion; D011458:Prostaglandins E / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology; D014655:Vascular Resistance; D014666:Vasomotor System / Q000502:physiology*
chemical_list: D011458:Prostaglandins E; D010643:Phenoxybenzamine; D006632:Histamine; D013806:Theophylline; D000241:Adenosine; D000109:Acetylcholine; D009638:Norepinephrine