Bursting firing of action potentials in central snail neurons elicited by d-amphetamine: role of cytoplasmic second messengers.
The role of the intracellular second messengers on the bursting firing of action potentials in central snail neurons elicited by d-amphetamine was studied in the identified RP4 neuron of the African snail Achatina fulica Ferussac. Oscillation of membrane potential and bursting firing of action potentials were elicited by d-amphetamine in a concentration dependent manner. The bursting firing of action potentials was decreased following extracellular application of (1) H8 (N-(2-methyl-amino) ethyl-3-isoquinoline sulphonamide dihydrochloride), a specific protein kinase A inhibitor and (2) anisomycin, a protein synthesis inhibitor. However, the bursting firing of action potentials were not affected after (1) extracellular application of H7 (1,(5-isoquinoline-sulphonyl)-2-methylpiperasine dihydrochloride), a specific protein kinase C (PKC) inhibitor, or (2) intracellular application of GDPbetaS, a G protein inhibitor. The oscillation of membrane potential of the bursting activity was blocked after intracellular injection of 3'-deoxyadenosine, an adenylyl-cyclase inhibitor. These results suggested that the bursting firing of action potentials elicited by d-amphetamine in snail neurons may be associated with the cyclic adenosine monophosphate (cAMP) second messenger system: on the other hand it may not be associated with the G protein and protein kinase C activity.
Chen
Y H
YH
Department of Pharmacology, College of Medicine, National Taiwan University, Taipei.
Tsai
M C
MC
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002490:Central Nervous System / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D003593:Cytoplasm / Q000187:drug effects / Q000502:physiology; D003913:Dextroamphetamine / Q000494:pharmacology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D009474:Neurons / Q000187:drug effects*; D015290:Second Messenger Systems / Q000502:physiology*; D012908:Snails / Q000502:physiology*
D018765:Dopamine Uptake Inhibitors; D009419:Nerve Tissue Proteins; D019204:GTP-Binding Proteins; D003913:Dextroamphetamine