MODULATORY EFFECT OF CAFFEINE ON GABA-ACTIVATED CURRENT FROM ACUTELY ISOLATED RAT DORSAL ROOT GANGLION NEURONS
- VernacularTitle:咖啡因对急性分离大鼠DRG神经元GABA-激活电流的调制作用
- Author:
Shao LI
;
Changkai SUN
;
Jian ZHANG
;
Aiping LI
;
Hua PIAO
;
Zhiwang LI
- Publication Type:Journal Article
- Keywords:
caffeine;
GABAA-receptor;
whole-cell patch clamp recording;
dorsal root ganglion;
rat
- From:
Chinese Journal of Neuroanatomy
2007;23(3):251-255
- CountryChina
- Language:Chinese
-
Abstract:
Whole-cell patch clamp technique was performed on acutely isolated rat dorsal root ganglion (DRG) neurons to investigate the modulatory effect of caffeine on γ-aminobutyric acid (GABA)-activated currents (IGABA). The results showed that the majority of the neurons examined (97.4%, 113/116) were sensitive to GABA. 1-1000 μmol/L GABA activated a concentration-dependent inward current which manifested obvious desensitization. After the neurons were treated with caffeine (0.01-100 μmol/L) prior to the application of GABA (100 μmol/L) for 30 s, GABA-activated membrane currents were obviously inhibited. Caffeine shifted the GABA dose-response curve downward and decreased the maximum response to 57% without changing Kd value. These results indicate that the inhibitory effect is non-competitive. Theophylline showed a similar and stronger inhibitory effect on IGABA. The pretreatment with caffeine (10 μmol/L) inhibited IGABA, which was potentized by diazepam (1 μmol/L). Intracellular application of H-8 almost completely abolished the inhibitory effect of caffeine on IGABA. The present results suggest that caffeine may be able to antagonize the effect of presynaptic inhibition of GABA in primary afferent.
