Vagal postganglionic origin of vasoactive intestinal polypeptide (VIP) mediating the vagal tachycardia.
Our aim was to confirm the role of postganglionic vagal fibres and vasoactive intestinal polypeptide (VIP) in mediating the vagal tachycardia in anaesthetised dogs. Vagal postganglionic stimulation after atenolol (1 mg/kg) and hexamethonium (10 mg/kg) caused a bradycardia (40 beats/min, n = 2), after atropine (0.5 mg/kg i.v.) the resulting tachycardia (37 beats/min) was attenuated by VIP receptor antagonism with VIP (6-28) (100 mug i.c.) by approximately 50%. VIP release from vagal postganglionic fibres mediates the vagal tachycardia.
Markos
F
F
Department of Physiology, University College Cork, Cork, Ireland. hazmarkos@yahoo.com
Snow
H M
HM
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D006328:Cardiac Catheterization; D003331:Coronary Vessels / Q000502:physiology; D004285:Dogs; D004558:Electric Stimulation; D005724:Ganglia / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects; D018005:Receptors, Vasoactive Intestinal Peptide / Q000187:drug effects / Q000378:metabolism; D013610:Tachycardia / Q000378:metabolism / Q000503:physiopathology*; D014630:Vagus Nerve / Q000378:metabolism / Q000503:physiopathology*; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism / Q000502:physiology*
D000319:Adrenergic beta-Antagonists; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D001262:Atenolol