GABA(A)- and AMPA-like receptors modulate the activity of an identified neuron within the central pattern generator of the pond snail Lymnaea stagnalis.
To examine the neurochemistry underlying the firing of the RPeD1 neuron in the respiratory central pattern generator of the pond snail, Lymnaea stagnalis, we examined electrophysiologically and pharmacologically either "active" or "silent" preparations by intracellular recording and pharmacology. GABA inhibited electrical firing by hyperpolarizing RPeD1, while picrotoxin, an antagonist of GABA(A) receptors, excited silent cells and reversed GABA-induced inhibition. Action potential activity was terminated by 1 mM glutamate (Glu) while silent cells were depolarized by the GluR agonists, AMPA, and NMDA. Kainate exerted a complex triphasic effect on membrane potential. However, only bath application of AMPA desensitized the firing. These data indicate that GABA inhibits RPeD1 via activation of GABA(A) receptors, while Glu stimulates the neuron by activating AMPA-sensitive GluRs.
Moccia
Francesco
F
Department of Structural and Functional Biology, University of Naples "Federico II" Complesso Universitario, Monte S. Angelo, viale Cinthia, 80126 Naples, Italy.
Di Cristo
Carlo
C
Winlow
William
W
Di Cosmo
Anna
A
D000818:Animals; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000187:drug effects / Q000502:physiology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D018698:Glutamic Acid / Q000494:pharmacology; D007608:Kainic Acid / Q000494:pharmacology; D008195:Lymnaea / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D016202:N-Methylaspartate / Q000494:pharmacology; D009433:Neural Inhibition / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010852:Picrotoxin / Q000494:pharmacology; D018091:Receptors, AMPA / Q000819:agonists / Q000378:metabolism*; D011963:Receptors, GABA-A / Q000378:metabolism*; D012119:Respiration; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D018755:GABA Agonists; D018756:GABA Antagonists; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D018698:Glutamic Acid; D007608:Kainic Acid; D016202:N-Methylaspartate; D010852:Picrotoxin; D018091:Receptors, AMPA; D011963:Receptors, GABA-A; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D005680:gamma-Aminobutyric Acid