Modulation of AMPA and NMDA responses in rat spinal dorsal horn neurons by trans-1-aminocyclopentane-1,3-dicarboxylic acid.

摘要: In freshly isolated spinal dorsal horn (DH) neurons (laminae I-IV) of the young rat effects 25-100 microM (+/-)-trans-1-aminocyclopentane-1,3-dicarboxylic acid (trans-ACPD), 1S,3R-ACPD and 1R,3S-ACPD, a metabotropic glutamate receptor (mGluR) agonist, on inward currents induced by (Glu), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA), N-methyl-D-aspartate (NMDA) kainate were studied under whole-cell voltage-clamp conditions. When cells clamped to -60 mV, racemic mixture both stereo isomers trans-ACPD increase responses elicited Glu, AMPA, NMDA, but little those kainate. addition, quisqualate (10-50 microM), in presence CNQX (5-20 microM) or NBQX (5 potentiated NMDA-induced currents. The enhancing effect lasted 10-75 min, depending upon dose length application. smaller proportion neurons, was preceded transient depression NMDA. 2-Amino-3-phosphonopropionic (L-AP3), putative antagonist mGluR exerted AMPA itself, reduced prevented 1S,3R-ACPD. It is concluded that activation trans-ACPD, its two enantiomers, may mediate enhancement NMDA acutely neurons. These results are consistent with possibility contribute regulation strength excitatory amino-mediated primary afferent neurotransmission, including nociception.