Facilitation of acetylcholine-evoked catecholamine release by cyclic AMP on isolated perfused dog adrenal glands.
The effects of cyclic nucleotides on catecholamine (CA) release and Ca2+ efflux were determined on isolated dog adrenals perfused with 1.3 mM Ca2+ containing fluid except indicated. Dibutyryl cyclic AMP (DBcAMP, 50 microM--1 mM) substantially enhanced CA release evoked by acetylcholine (ACh) and slightly increased the spontaneous CA release. Dibutyryl cyclic GMP (100-500 microM) narrowly increased the basal CA release. DBcAMP, 200 microM also significantly facilitated CA release caused by nicotine, bethanechol and excess K+, and by caffeine in the absence of extracellular Ca2+. 45Ca efflux evoked by ACh and by caffeine in the absence of extracellular Ca2+ from prelabelled adrenals with 45Ca was enhanced significantly by DBcAMP, 200 microM. These results suggest that cAMP may function as a facilitatory modulator in CA release from the adrenal medulla via in part the effect on Ca2+ flux including alterations in the function of systems for intracellular Ca2+ homeostasis.
D000109:Acetylcholine / Q000494:pharmacology*; D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002132:Calcium Radioisotopes; D002395:Catecholamines / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D004285:Dogs; D066298:In Vitro Techniques; D013012:Sorbitol / Q000378:metabolism
D002132:Calcium Radioisotopes; D002395:Catecholamines; D013012:Sorbitol; D003994:Bucladesine; D000242:Cyclic AMP; D000109:Acetylcholine; D002118:Calcium