title: Stimulation of adenosine A1 and A2A receptors by AMP in the submucosal plexus of guinea pig small intestine.
abstract: Actions of adenosine 5'-monophosphate (AMP) on electrical and synaptic behavior of submucosal neurons in guinea pig small intestine were studied with "sharp" intracellular microelectrodes. Application of AMP (0.3-100 microM) evoked slowly activating depolarizing responses associated with increased excitability in 80.5% of the neurons. The responses were concentration dependent with an EC(50) of 3.5 +/- 0.5 microM. They were abolished by the adenosine A(2A) receptor antagonist ZM-241385 but not by pyridoxal-phosphate-6-azophenyl-2,4-disulfonic acid, trinitrophenyl-ATP, 8-cyclopentyl-1,3-dimethylxanthine, suramin, or MRS-12201220. The AMP-evoked responses were insensitive to AACOCF3 or ryanodine. They were reduced significantly by 1) U-73122, which is a phospholipase C inhibitor; 2) cyclopiazonic acid, which blocks the Ca(2+) pump in intraneuronal membranes; and 3) 2-aminoethoxy-diphenylborane, which is an inositol (1,4,5)-trisphosphate receptor antagonist. Inhibitors of PKC or calmodulin-dependent protein kinase also suppressed the AMP-evoked excitatory responses. Exposure to AMP suppressed fast nicotinic ionotropic postsynaptic potentials, slow metabotropic excitatory postsynaptic potentials, and slow noradrenergic inhibitory postsynaptic potentials in the submucosal plexus. Inhibition of each form of synaptic transmission reflected action at presynaptic inhibitory adenosine A(1) receptors. Slow excitatory postsynaptic potentials, which were mediated by the release of ATP and stimulation of P2Y(1) purinergic receptors in the submucosal plexus, were not suppressed by AMP. The results suggest an excitatory action of AMP at adenosine A(2A) receptors on neuronal cell bodies and presynaptic inhibitory actions mediated by adenosine A(1) receptors for most forms of neurotransmission in the submucosal plexus, with the exception of slow excitatory purinergic transmission mediated by the P2Y(1) receptor subtype.
authors.affiliation: Dept of Physiology and Cell Biology, Columbus, OH 43210-1218, USA.
authors.forename: Na
authors.initials: N
authors.lastname: Gao
authors.forename: Hong-Zhen
authors.initials: HZ
authors.lastname: Hu
authors.forename: Sumei
authors.initials: S
authors.lastname: Liu
authors.forename: Chuanyun
authors.initials: C
authors.lastname: Gao
authors.forename: Yun
authors.initials: Y
authors.lastname: Xia
authors.forename: Jackie D
authors.initials: JD
authors.lastname: Wood
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D058916:Adenosine A1 Receptor Antagonists; D058917:Adenosine A2 Receptor Antagonists; D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000249:Adenosine Monophosphate / Q000494:pharmacology*; D000818:Animals; D001896:Boron Compounds / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D007211:Indoles / Q000494:pharmacology; D008297:Male; D008301:Maleimides / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D010627:Phenethylamines / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology; D043682:Receptor, Adenosine A1 / Q000502:physiology*; D043705:Receptor, Adenosine A2A / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects; D013368:Submucous Plexus / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects; D013779:Tetrodotoxin / Q000494:pharmacology; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology; D014227:Triazines / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology
chemical_list: C110041:9-chloro-2-(2-furyl)-5-phenylacetylamino(1,2,4)triazolo(1,5-c)quinazoline; D058916:Adenosine A1 Receptor Antagonists; D058917:Adenosine A2 Receptor Antagonists; D001896:Boron Compounds; D004791:Enzyme Inhibitors; D004963:Estrenes; D007211:Indoles; D008301:Maleimides; C111914:N(6)-methyl-2'-deoxyadenosine 3',5'-diphosphate; D010627:Phenethylamines; D011760:Pyrrolidinones; D011799:Quinazolines; D043682:Receptor, Adenosine A1; D043705:Receptor, Adenosine A2A; D014227:Triazines; D014230:Triazoles; C097270:ZM 241385; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; C053907:8-cyclopentyl-1,3-dimethylxanthine; D000249:Adenosine Monophosphate; D013779:Tetrodotoxin; D000244:Adenosine Diphosphate; C063302:KN 62; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D013806:Theophylline; C109986:2-aminoethoxydiphenyl borate; D000241:Adenosine; C070515:bisindolylmaleimide I; D009638:Norepinephrine; C000543:cyclopiazonic acid