title: Intraneuronal guanylyl-imidodiphosphate injection mimics long-term synaptic hyperpolarization in Aplysia.
abstract: The phosphodiesterase (3':5'-cyclic AMP 5'-nucleotidohydrolase, EC 3.1.4.17) inhibitor thepohylline enhances both the amplitude and duration of a long-lasting synaptic hyperpolarization in identified neuron R15 in Aplysia californica. Intraneuronal injection into R15 of glanylyl-imidodiphosphate, an adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] activator, results in a deep and long-lasting hyperpolarization of the cell, similar to that produced by synaptic stimulation. Biochemical analysis confirms that guanylyl-imidodiphosphate activates adenylate cyclase in Aplysia californica nervous tissue, without affecting phosphodiesterase activity. These observations suggest that adenosine 3':5'-cyclic monophosphate plays a role in long-lasting synaptic inhibition and are consistent with a post-synaptic site of action for adenosine 3':5'-cyclic monophosphate.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D000242:Cyclic AMP / Q000502:physiology; D004789:Enzyme Activation; D006150:Guanine Nucleotides / Q000494:pharmacology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects*; D008974:Mollusca; D013569:Synapses / Q000502:physiology*; D013806:Theophylline / Q000494:pharmacology
chemical_list: D006150:Guanine Nucleotides; D013806:Theophylline; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D000262:Adenylyl Cyclases