Action of sympathomimetic drugs on the bronchial circulation of the horse.
In the quietly standing horse I.V. administration of adrenaline decreased, and of dobutamine increased, bronchial artery flow. These changes paralleled changes in arterial pressure. With phenylephrine and noradrenaline bronchial artery flow decreased while arterial pressure increased, indicating active vasoconstriction in the bronchial circulation. With clenbuterol an increase in bronchial artery flow was accompanied by a decrease in systemic blood pressure, indicating bronchial arterial vasodilatation. We conclude that alpha-constrictor and beta 2-dilator receptors are present in the bronchial artery bed and that stimulation of these receptors could explain changes in flow seen in the horse during exercise and anaesthesia.
Sanders
E A
EA
Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
Gleed
R D
RD
Hackett
R P
RP
Dobson
A
A
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001980:Bronchi / Q000098:blood supply / Q000187:drug effects*; D001981:Bronchial Arteries / Q000187:drug effects / Q000502:physiology; D002976:Clenbuterol / Q000494:pharmacology; D004280:Dobutamine / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D006736:Horses; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000187:drug effects / Q000502:physiology; D012039:Regional Blood Flow / Q000187:drug effects; D013566:Sympathomimetics / Q000494:pharmacology*
D011941:Receptors, Adrenergic; D013566:Sympathomimetics; D010656:Phenylephrine; D004280:Dobutamine; D009638:Norepinephrine; D002976:Clenbuterol; D004837:Epinephrine