Veterinary Neuropharmacology

ADRENERGIC RECEPTORS AND ADRENERGIC RESPONSES

α actions	β actions
Constriction of arterioles and veins – rise in BP	Dilatation of arterioles and veins – fall in BP
Heart – little action, arrhythmia in high doses	Cardiac stimulation, increased heart rate, force and conduction velocity
-	Bronchodilatation
Contraction of radial muscles of the eye – mydriasis, decreased aqueous secretion	No effect on iris and ciliary muscles, enhanced aqueous secretion
Intestinal relaxation, contraction of sphincters	Intestinal relaxation
Bladder trigone – contraction	Detrusor - relaxation
Uterus – contraction	Relaxation
Splenic capsule – contraction	Relaxation
Neuromuscular transmission facilitated – increased Ach	Active state – prolonged in fast contracting muscle, abbreviated in slow contracting muscle
Insulin secretion inhibited ( œ2 dominant)	Augmented insulin (mild)
Liver – glycogenolysis	-
-	Renin release from the kidney
Male sex organs – ejaculation	-
Salivary glands – K+ and H2O secretion	Ptylin secretion
-	ADH secretion from posterior pituitary
Nictitating membrane – contraction in some species	-