The Development of Phasic and Tonic Inhibition in the Rat Visual Cortex.
10.4196/kjpp.2010.14.6.399
- Author:
Hyun Jong JANG
1
;
Kwang Hyun CHO
;
Sung Won PARK
;
Myung Jun KIM
;
Shin Hee YOON
;
Duck Joo RHIE
Author Information
1. Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea. djrhie@catholic.ac.kr
- Publication Type:Original Article
- Keywords:
Development;
GABA;
Inhibition;
Tonic inhibition;
Visual cortex
- MeSH:
Animals;
Electric Stimulation;
gamma-Aminobutyric Acid;
Inhibitory Postsynaptic Potentials;
Kinetics;
Membranes;
Plastics;
Rats;
Visual Cortex
- From:The Korean Journal of Physiology and Pharmacology
2010;14(6):399-405
- CountryRepublic of Korea
- Language:English
-
Abstract:
Gamma-aminobutyric acid (GABA)-ergic inhibition is important in the function of the visual cortex. In a previous study, we reported a developmental increase in GABAA receptor-mediated inhibition in the rat visual cortex from 3 to 5 weeks of age. Because this developmental increase is crucial to the regulation of the induction of long-term synaptic plasticity, in the present study we investigated in detail the postnatal development of phasic and tonic inhibition. The amplitude of phasic inhibition evoked by electrical stimulation increased during development from 3 to 8 weeks of age, and the peak time and decay kinetics of inhibitory postsynaptic potential (IPSP) and current (IPSC) slowed progressively. Since the membrane time constant decreased during this period, passive membrane properties might not be involved in the kinetic changes of IPSP and IPSC. Tonic inhibition, another mode of GABAA receptor-mediated inhibition, also increased developmentally and reached a plateau at 5 weeks of age. These results indicate that the time course of the postnatal development of GABAergic inhibition matched well that of the functional maturation of the visual cortex. Thus, the present study provides significant insight into the roles of inhibitory development in the functional maturation of the visual cortical circuits.
