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Possible presynaptic inhibition in rat olfactory cortex.
Author(s) -
Pickles H G,
Simmonds M A
Publication year - 1976
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1976.sp011526
Subject(s) - antidromic , stimulation , neuroscience , depolarization , chemistry , stimulus (psychology) , bicuculline , physics , biophysics , biology , psychology , antagonist , biochemistry , receptor , psychotherapist
1. Field potentials were evoked from rat olfactory cortex slices in vitro at room temperature by lateral olfactory tract stimulation. At very slow stimulation rates (less than 0‐1 Hz) a delayed negative wave (late N‐wave) was found to follow the first negative wave (N‐wave). This late N‐wave started 30 msec after the stimulus and lasted for 50‐150 msec. 2. Low Ca2+/high Mg2+ medium abolished the late N‐wave more rapidly than the N‐wave, suggesting a possible multisynaptic origin. 3. The GABA antagonist bicuculline (10(‐6) M) abolished the late N‐wave without affecting the N‐wave. 4. During the late N‐wave, both the tract action potential and the N‐wave to a second stimulus were reduced. This was attributed, at least in part, to collision with antidromic action potentials which could be detected during the late N‐wave. 5. These findings are discussed in terms of a possible presynaptic depolarizing action of a GABA‐like transmitter giving rise to presynaptic inhibition and the late N‐wave.