Histamine slows the onset of desensitization of rat cortical NMDA receptors.
The effects of histamine on N-methyl-d-aspartate (NMDA) receptor-mediated ion current in cultured rat cortical neurones have been investigated by superfusion of voltage-clamped (-80 mV) cells with 100 mM NMDA and with various concentrations of histamine. In a subpopulation of the neurones tested (30/53), histamine (10-100 mM) enhanced the peak amplitude, and slowed down the onset of desensitization of the NMDA-induced ion currents, both in a concentration-dependent manner. No effects of histamine on the kinetics of recovery from desensitization were detected. In other neurones (21/53), histamine had no effect on the NMDA-induced currents and in two of the neurones tested histamine potentiated NMDA-induced currents without a detectable effect on desensitization kinetics. The results indicate that in a subpopulation of rat cortical neurones histamine potentiates NMDA-induced ion currents by slowing the kinetics of onset of desensitization.
Zwart
R
R
Department of Molecular Neuroendocrinology, Max Planck Institute for Experimental Medicine, Göttingen, Germany.
Blank
T
T
Spiess
J
J
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000502:physiology*; D006632:Histamine / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D016202:N-Methylaspartate / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; D006632:Histamine