Synaptic contact between mechanosensory neuron and withdrawal interneuron in terrestrial snail is mediated by L-glutamate-like transmitter.
The properties of the monosynaptic input from mechanosensory neurons to withdrawal interneurons were examined in Helix lucorum. The instantaneous I-V relation of the excitatory postsynaptic current in withdrawal interneurons was nonlinear, having a plateau region between -40 and -60 mV. On application of the blocker of vertebrate N-methyl-D-aspartate (NMDA) receptors AP5, or reduction of the Mg(2+) concentration, the current-voltage relation became more linear, suggesting that Mg(2+) may partially block the ion channel underlying the EPSC at voltages ranging from -40 to around -60 mV and the involvement of NMDA-like receptors. DNQX and 6-cyano-7-nitroquinoxaline-2,3-dione, which are known to block the glutamate non-NMDA receptors in mammals, significantly depress in a dose-dependent manner the actions of the natural transmitter. Exogenous L-glutamate applications mimicked the action of the mechanosensory neuron transmitter.
Bravarenko
N I
NI
Institute of Higher Nervous Activity and Neurophysiology, Butlerova 5A, Moscow 117485, Russia.
Korshunova
T A
TA
Malyshev
A Y
AY
Balaban
P M
PM
D000818:Animals; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000494:pharmacology*; D006372:Helix, Snails / Q000187:drug effects* / Q000502:physiology; D007395:Interneurons / Q000187:drug effects* / Q000502:physiology; D008465:Mechanoreceptors / Q000187:drug effects* / Q000502:physiology; D040542:Mechanotransduction, Cellular / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D013569:Synapses / Q000187:drug effects* / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists; D018698:Glutamic Acid