Journal
PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY
Volume 443, Issue 5-6, Pages 707-712Publisher
SPRINGER-VERLAG
DOI: 10.1007/s00424-001-0740-6
Keywords
cultured neurones; desensitization; GABA; GABA(A) receptor; iontophoresis; striatum
Categories
Ask authors/readers for more resources
GABA(A) receptor-mediated Cl- currents were evoked by rapid and short (0.75-1.5 ms), focal iontophoretic applications of GABA to proximal dendrites of cultured striatal neurones. The mean amplitude (232+/-21.0 pA) was in the range of large miniature inhibitory postsynaptic currents (mIPSCs), while the 10-90% rise times (3.4+/-0.20 ms) and the time constants of decay (60.0+/-8.4 ms) were three times slower. Responses to paired-pulse application of GABA at inter-pulse intervals (IPIs) of 30, 100 and 300 ms showed no depression of the second response (R2) relative to the first (R1). At short IPIs, at which RI and R2 showed temporal summation, the net amplitude of R2 (R2(net)) was partially occluded. Lowering the iontophoretic intensity during paired-pulse application at an IPI of 30 ins reduced R1 by 69.5+/-3.3%, while occlusion of R2(net) decreased significantly, indicating that the receptor occupancy had been lowered. During the course of ten pulses of GABA at 10 Hz, responses declined by 8.7+/-3.9%, which probably reflects slow cumulative desensitization. In conclusion, rapid focal iontophoresis of exogenous GABA onto GABA(A) receptors does not result in activity-dependent depression of the postsynaptic response. This result suggests that fast desensitization is unlikely to occur during repetitive GABA(A) receptor-mediated synaptic transmission in striatal neurones.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available