Ontogeny of cholinergic and adrenergic cardiovascular regulation in the domestic chicken (Gallus gallus).
Adrenergic and cholinergic tone on the cardiovascular system of embryonic chickens was determined during days 12, 15, 19, 20, and 21 of development. Administration of the muscarinic antagonist atropine (1 mg/kg) resulted in no significant change in heart rate or arterial pressure at any developmental age. In addition, the general cardiovascular depressive effects of hypoxia were unaltered by pretreatment with atropine. In addition, the ganglionic blocking agent hexamethonium (25 mg/kg) did not induce changes in heart rate. The beta-adrenergic antagonist propranolol (3 mg/kg) induced a bradycardia of similar magnitude on all days studied, with a transient hypertensive action on days 19-20, indicating the existence of an important cardiac and vascular beta-adrenergic tone. Injections of the alpha-adrenergic antagonists prazosin or phentolamine (1 mg/kg) reduced arterial pressure significantly on all days of incubation studied. Collectively, the data indicate that embryonic chickens rely primarily on adrenergic control of cardiovascular function, with no contribution from the parasympathetic nervous system.
Crossley
D
D
Department of Biological Sciences, University of North Texas, Denton, Texas 76201, USA. dcrissle@uci.com
Altimiras
J
J
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000166:cytology / Q000187:drug effects / Q000196:embryology*; D001794:Blood Pressure / Q000187:drug effects; D002319:Cardiovascular System / Q000196:embryology / Q000294:innervation; D002395:Catecholamines / Q000097:blood; D002642:Chick Embryo; D002645:Chickens; D002799:Cholinergic Fibers / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D005730:Ganglionic Blockers / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D018738:Hexamethonium / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000502:physiology*; D014630:Vagus Nerve / Q000166:cytology / Q000187:drug effects / Q000196:embryology*
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D002395:Catecholamines; D005730:Ganglionic Blockers; D018727:Muscarinic Antagonists; D011941:Receptors, Adrenergic; D018738:Hexamethonium; D001285:Atropine; D011433:Propranolol; D011224:Prazosin; D010646:Phentolamine