Ionotropic glutamate-receptor antagonists inhibit the aversive effects of nitric oxide donor injected into the dorsolateral periaqueductal gray of rats.
BACKGROUND
Nitric oxide (NO) is a gas neurotransmitter that may facilitate glutamate release in the central nervous system. NO donors or glutamate agonists injected into the dorsolateral periaqueductal grey (dlPAG) induce flight behaviour.


OBJECTIVE
To test the hypothesis that the defensive reactions induced by an NO donor in the dlPAG would be attenuated by pretreatment with AMPA/kainate or NMDA glutamate receptor antagonists.


METHODS
Male Wistar rats with cannulae aimed at the dlPAG received vehicle, AP7 (a NMDA receptor antagonist, 2 nmol) or NBQX (an AMPA/kainite receptor antagonist, 100 nmol) injection 10 min before the administration of SIN-1 (an NO donor, 300 nmol). Immediately after the last injection, their behavior was observed in an open arena during 10 min.


RESULTS
SIN-1 induced flight reactions characterized by running and jumps. Pretreatment with AP7 or NBQX completely prevented the effects of SIN-1.


CONCLUSIONS
The results suggest that the aversive reactions induced by an NO donor in the dlPAG depend on ionotropic glutamate receptor activation.
Moreira
Fabrício Araújo
FA
Department of Pharmacology, FMRP, Campus USP, 14049-900, Ribeirão Preto, SP, Brazil.
Molchanov
Moriana Ludmilla
ML
Guimarães
Francisco Silveira
FS
D015763:2-Amino-5-phosphonovalerate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D008297:Male; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects*; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D010487:Periaqueductal Gray / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000819:agonists / Q000037:antagonists & inhibitors; D018092:Kainic Acid Receptors / Q000819:agonists / Q000037:antagonists & inhibitors; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000037:antagonists & inhibitors; D013997:Time Factors
D015763:2-Amino-5-phosphonovalerate; D018691:Excitatory Amino Acid Antagonists; D008981:Molsidomine; D009569:Nitric Oxide; D020030:Nitric Oxide Donors; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate; C002385:linsidomine; C031231:2-amino-7-phosphonoheptanoic acid