Deactivation and desensitization of non-NMDA receptors in patches and the time course of EPSCs in rat cerebellar granule cells.
AUTOR(ES)
Silver, R A
RESUMO
1. Spontaneous and evoked non-NMDA receptor-mediated EPSCs were recorded from cerebellar granule cells in slices at approximately 24 and approximately 34 degrees C. The EPSC decay was fitted with the sum of two exponential functions. 2. The time courses of non-NMDA receptor deactivation and desensitization were determined with fast concentration jumps of glutamate onto patches from cultured granule cells. Deactivation (decay time constant tau = 0.6 ms at 24 degrees C) was substantially faster than desensitization (tau = 4 ms). Both processes were fitted by single exponential functions. 3. The decay of the fast component of the spontaneous EPSC (tau EPSCfast = 0.9 ms at 23 degrees C) was marginally slower than deactivation but too fast to be determined by desensitization. Our results suggest that the decay of this component is set by both the rate of decline of transmitter concentration and channel deactivation. 4. A simple diffusion model predicts that the time course of transmitter in the cleft declines slowly during the later stages of its action. The slow phase of transmitter removal could account for the time course of the slow component of the spontaneous EPSC (tau EPSCslow = 8 ms at 23 degrees C).
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1158958Documentos Relacionados
- Deactivation and desensitization of non-NMDA receptors in patches and the time course of EPSCs in rat cerebellar granule cells
- Evidence for more than one type of non-NMDA receptor in outside-out patches from cerebellar granule cells of the rat.
- A comparison of non-NMDA receptor channels in type-2 astrocytes and granule cells from rat cerebellum.
- Three-dimensional models of non-NMDA glutamate receptors.
- Sensory input and burst firing output of rat and cat thalamocortical cells: the role of NMDA and non-NMDA receptors.