حاصرات مستقبِل الغلوتامات الأيونوتروبي

Ionotropic glutamate receptors are ligand-gated cation channels for glutamate, the principal excitatory transmitter of the central nervous system. The NMDA type is a heterotetrameric channel with high calcium permeability whose activation requires three things at once: L-glutamate at the GluN2 subunit, glycine or D-serine at the GluN1 subunit, and membrane depolarisation sufficient to lift the voltage-dependent magnesium block. Drugs in this class block such a channel: UniProt records that dizocilpine causes long-lasting and almost complete block of NMDA receptor activity, and that 2-amino-5-phosphonovalerate almost completely blocks it while 7-chlorokynurenate partially inhibits it. The label for one member, ketamine, describes the resulting state of unconsciousness as 'dissociative' anaesthesia, in which association pathways to the brain appear to be interrupted before somesthetic sensory blockade is produced. The class is mixed: the cited list also holds acamprosate, whose action is not clean ionotropic channel block, and butobarbital, a barbiturate.