title: Stimulation of acetylcholine release from myenteric neurons of guinea pig small intestine by forskolin and cyclic AMP.
abstract: Forskolin, an activator of adenylate cyclase, was used to examine the regulation of [3H]acetylcholine (ACh) release by cyclic AMP (cAMP)-related mechanisms in myenteric plexus-longitudinal muscle preparations of guinea pig small intestine. Forskolin evoked a dose-related increase in [3H]ACh release. Both dibutyryl-cAMP and 8-Br-cAMP significantly elevated [3H]ACh secretion. In the presence of phosphodiesterase inhibitors (theophylline and 3-isobutyl-1-methylxanthine), the basal [3H]ACh output was increased. There was a significantly greater stimulation when forskolin was used to incite endogenous cAMP synthesis and phosphodiesterase inhibitors were simultaneously applied to prevent cAMP breakdown. The enhancement of forskolin-stimulated release by theophylline or 3-isobutyl-1-methylxanthine strongly implicates a synergistic interaction between the two. These findings suggest that forskolin acts to increase ACh release by a modulation of endogenous cAMP and further support a cAMP-mediated mechanism in the secretion of ACh from myenteric cholinergic neurons.
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000294:innervation; D009119:Muscle Contraction / Q000187:drug effects; D009197:Myenteric Plexus / Q000187:drug effects* / Q000378:metabolism; D013806:Theophylline / Q000494:pharmacology
chemical_list: D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D003994:Bucladesine; D013806:Theophylline; D000242:Cyclic AMP; D000109:Acetylcholine; D015056:1-Methyl-3-isobutylxanthine