Effect of bilateral destruction of the subretrofacial area on central inspiratory activity of the respiratory center and on the respiratory response to hypercapnia

NMDA Receptors of A5 Area in the Regulation of Blood Pressure and Respiratory Activity during Hypoxia in Rats

In narcotized (40 mg/kg sodium ethaminal intraperitoneally) spontaneously breathing albino rats, experimental short-term hypoxia induced BP drop and increased phrenic nerve firing rate. Unilateral microinjection of a selective NMDA receptor blocker ketamine hydrochloride (50 nl; 4 mM) into A5 area did not affect BP and phrenic nerve fi ring rate. However, against the background of preliminary NMDA receptor blockage, hypoxia more markedly stimulated rhythmic activity of the respiratory center and hypotensive response. Unilateral microinjection of a selective blocker of non-NMDA receptors GAMS (50 nl; 4 mM) into A5 area did not change initial BP and phrenic nerve fi ring rate. The studied parameters in rats exposed to hypoxia after blockage of non-NMDA receptors in A5 area did not differ from the control levels. Thus, activity of the respiratory center and BP in rats during hypoxia is regulated by the structures in A5 area and NMDA glutamate receptors.