ISSN:
1432-1351
Keywords:
Key words Iontophoresis
;
Inferior colliculus
;
Amphibian
;
Rana pipiens
;
Bicuculline
;
GABA
;
AbbreviationsBIC bicuculline methiodide
;
CF characteristic frequency
;
DNLL dorsal nucleus of the lateral lemniscus
;
eFTC excitatory frequency tuning curve
;
GABAγ-amino butyric acid
;
IC inferior colliculus
;
iFTC inhibitory frequency tuning curve
;
PB phasic burst
;
PL-1 primary-like 1
;
PL-2 primary-like 2
;
PL-3 primary-like 3
;
PSTH post-stimulus time histogram
;
SPL sound pressure level
;
SRN superficial reticular nucleus
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract The functional role of GABAergic inhibition in shaping the frequency tuning of 96 neurons in the torus semicircularis of the leopard frog, Rana pipiens, was studied using microiontophoresis of the GABAA receptor antagonist, bicuculline methiodide. Bicuculline application abolished, or reduced in size, the inhibitory tuning curves of 72 neurons. In each case, there was a concommitant broadening of the excitatory tuning curve such that frequency-intensity combinations that were inhibitory under control conditions, became excitatory during disinhibition with bicuculline methiodide. These effects were observed irrespective of the excitatory tuning curve configuration prior to bicuculline methiodide application. Results indicate an important role for GABA-mediated inhibition in shaping the frequency selectivity of neurons in the torus semicircularis of the leopard frog. Bicuculline application also affected several other response properties of neurons in the leopard frog torus. Disinhibition with bicuculline methiodide increased both the spontaneous firing rate (18 cells) and stimulus-evoked discharge rate (81 cells) of torus neurons, decreased the minimum excitatory threshold for 18 cells, and altered the temporal discharge pattern of 47 neurons. Additional roles for GABAergic inhibition in monaural signal analysis are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003590050409
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