Role of adenosine 3',5'-cyclic monophosphate in adrenoceptor-mediated control of 3H-noradrenaline secretion in guinea-pig ileum myenteric nerve terminals.
Secretion of 3H-noradrenaline was evoked by electrical field stimulation (1 Hz, 300 shocks) in guinea-pig ileum myenteric plexus. The role of cyclic nucleotides in the presynaptic receptor-mediated control of 3H-noradrenaline secretion was studied. The secretion of 3H-noradrenaline was maximally enhanced to the same extent, viz. 300-400% of control, by two analogues of cyclic AMP (8-Br cyclic AMP and dibutyryl cyclic AMP), by an adenylate cyclase activator (forskolin) and by three structurally different inhibitors of phosphodiesterase (3-isobutyl-1-methylxanthine, SQ 20,006 and Ro 20-1724), but not altered by two analogues of cyclic GMP (8-Br cyclic GMP and dibutyryl cyclic GMP). Added separately an alpha 2-adrenoceptor antagonist (yohimbine) and a beta-adrenoceptor agonist (isoprenaline) enhanced the 3H-noradrenaline secretion. Yohimbine, but not isoprenaline, increased additively the 'maximal enhancement' of the 3H-noradrenaline secretion caused by 3-isobutyl-1-methylxanthine. These results suggest that neuronal cyclic AMP may be involved in beta- but not in alpha-adrenoceptor-mediated control of 3H-noradrenaline secretion in guinea-pig ileum myenteric nerve terminals.
Alberts
P
P
Ogren
V R
VR
Sellström
A I
AI
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D012368:4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone / Q000494:pharmacology; D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D006168:Guinea Pigs; D007082:Ileum / Q000294:innervation; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009197:Myenteric Plexus / Q000378:metabolism*; D009411:Nerve Endings / Q000378:metabolism; D009539:Nicotinic Acids / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology
D009539:Nicotinic Acids; D010726:Phosphodiesterase Inhibitors; D011941:Receptors, Adrenergic; D005576:Colforsin; D012368:4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone; D015016:Yohimbine; C011610:SQ 20006; D011433:Propranolol; D000242:Cyclic AMP; D006152:Cyclic GMP; D007545:Isoproterenol; D015056:1-Methyl-3-isobutylxanthine; D009638:Norepinephrine