2024-03-28T08:51:15Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/325022011-02-16T23:00:00Zcom_10261_54com_10261_1col_10261_307
00925njm 22002777a 4500
dc
Lerma Gómez, Juan
author
1992-02
The action of the endogenous polyamine spermine on NMDA-induced responses (in the presence of glycine) was evaluated in cultured spinal cord neurons under voltage- and concentration-clamp conditions. Spermine potentiated NMDA-induced responses in a dose-dependent manner. It was more effective in potentiating steadystate currents (i.e., desensitized response) than the peak phase of the response, indicating that the degree of desensitization was reduced in the presence of the polyamine. Kinetic analysis revealed that the desensitization onset rate, but not recovery rate, was affected by spermine. The effect was voltage independent and was seen in thoroughly dialyzed cells, in which desensitization becomes independent of glycine. Spermine potentiation showed fast on-off kinetics, and intracellular spermine, loaded in the recording pipette, did not occlude potentiation by extracellularly applied spermine. These results are consistent with the existence of a modulatory site for polyamines in the extracellular domain of the NMDA receptor, the activation of which potentiates NMDA receptor function by regulating its desensitization kinetics.
Neuron 8(2): 343-352 (1992)
0896-6273
http://hdl.handle.net/10261/32502
10.1016/0896-6273(92)90300-3
Spermine regulates N-methyl-D -aspartate receptor desensitization