[Burst spikes induced by lidocaine in the ganglion of Lymnaea stagnalis].
BACKGROUND
To investigate the burst spikes (BS) induced by lidocaine in the ganglion of Lymnaea stagnalis, we used a multielectrode dish for extracellular recording in many points simultaneously.


METHODS
Ganglion of Lymnaea stagnalis was placed in the multielectrode dish that has 64 planar microelectrodes. After the basal electrophysiological recordings of neuronal activity in the ganglion, the lidocaine concentrations were increased from 1 to 1,000 microg x ml(-1).


RESULTS
A sequence of changes was observed. The initial stage was represented before first BS. Second stage was during first BS (lidocaine concentrations were between 18 +/- 3 and 105 +/- 69 microg x ml(-1)). Third stage was the period before the second BS. The fourth stage was during second BS (lidocaine concentrations were more than 670 +/- 254 microg x ml(-1)). Basic unit frequency of firing were 83 +/- 33% at first stage, 91 +/- 280% at second stage, 77 +/- 29% at third stage, and 50 +/- 41% at fourth stage (P < 0.05) compared to control (100%).


CONCLUSIONS
The results of this study showed that the lidocaine induced BS with low and high lidocaine concentrations have different mechanisms in the central nervous system of Lymnaea stagnalis.
Kasaba
Toshiharu
T
Department of Anesthesiology and Intensive Care, Pathophysiological Diagnosis and Therapy, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692.
Onizuka
Shin
S
Kashiwada
Masatoshi
M
Takasaki
Mayumi
M
D000200:Action Potentials / Q000187:drug effects*; D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D017952:Ganglia, Invertebrate / Q000187:drug effects* / Q000502:physiology*; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology*; D008195:Lymnaea; D008839:Microelectrodes
D000779:Anesthetics, Local; D008012:Lidocaine