Identification and characterization of adrenergic receptors and catecholamine-stimulated adenylate cyclase in hog pial membranes.
In order to define the adrenergic receptors in small pial blood vessels, we studied [3H]dihydroalprenolol (DHA) binding, [3H]dihydroergocryptine (DHE) binding, and catecholamine-stimulated adenylate cyclase in membranes prepared from the hog pia. [3H]dha bound to a saturable number of sites (0.09 pmol/mg protein) with a high affinity to (10 mM). The ability of a small series of adrenergic agents to compete for [3H]DHA binding was as expected for binding to beta-adrenergic membrane receptors. The receptor binding appeared to be composed largely of beta 2-adrenergic sites but some sites with beta 1 properties were detected. The beta-adrenergic agonist, isoproterenol, stimulated adenylate cyclase activity by 20% in pial membranes in the presence of GTP. The potency of catecholamines in stimulating adenylate cyclase correlated well with theif sites (0.39 pmol/mg) on these membranes. alpha-Adrenergic agents were potent competitors for [3H]DHE binding but dopamine, serotonin and histamine had effects only at high concentrations. These data demonstrate the presence of alpha- and beta-adrenergic membrane receptors and beta-adrenergically stimulated adenylate cyclase activity in small pial blood vessels from the hog.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D001160:Arterioles / Q000294:innervation; D002395:Catecholamines / Q000494:pharmacology*; D002531:Cerebellum / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism; D004082:Dihydroalprenolol / Q000378:metabolism; D004088:Dihydroergotoxine / Q000378:metabolism; D010841:Pia Mater / Q000098:blood supply / Q000201:enzymology*; D011869:Radioligand Assay; D011941:Receptors, Adrenergic / Q000187:drug effects / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D013552:Swine
D002395:Catecholamines; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D004088:Dihydroergotoxine; D004082:Dihydroalprenolol; D000255:Adenosine Triphosphate; D000262:Adenylyl Cyclases