The effects of several N-methyl-D-aspartate (NMDA) receptorand sigma receptor-related compounds on the discriminative stimulus effects of phencyclidine (PCP) were examined in rats trained to discriminate PCP (1.5 mg/kg, i.p.) from saline under a two-lever fixed ratio 20 schedule of food reinforcement. PCP produced a dose-dependent increase in PCP-appropriate responding. A non-competitive NMDA r...

Sigma (sigma) ligands have been shown to modulate NMDA receptor activity. In the present study we used the olfactory bulbectomy (OBX) animal model of depression to assess the effects of the sigma1 ligand igmesine on OBX-induced behaviour. Behavioural experiments demonstrated OBX (saline-treated) rats to have increased dizocilpine-induced behavioural modifications, including locomotor and circli...

Female rats were exposed to 0, 0.5, or 6.4 ppm methylmercury in their drinking water before mating, and throughout gestation and lactation. When the female offspring were 4-6 months old, they were trained to respond under a multiple differential reinforcement of high rate (DRH) 9:4-- Extinction schedule of reinforcement. No differences among exposure groups were apparent in steady-state behavio...

Propofol is a rapidly acting water-insoluble non-barbiturate anesthetic agent that is widely used as an intravenous sedative-hypnotic agent. Anecdotal evidence indicates that propofol may be effective at terminating intractable migraine headache. Cortical spreading depression (CSD) is believed to be the neural correlate of migraine aura and may be a trigger for migraine pain. Agents that block ...

MK-801 impaired social recognition potency of adult male rats when given immediately after the initial interaction with a juvenile rat. Administration of kynurenic acid prior to the initial interaction protected the adults against recognition deficits induced by MK-801. When re-exposed at a delay of 30 min to the familiar juvenile, social investigation in the adults was significantly reduced. T...

Systemic administration of cholecystokinin (CCK) inhibits a subpopulation of rostral ventrolateral medulla (RVLM) presympathetic vasomotor neurons. This study was designed to determine whether this effect involved subdiaphragmatic vagal afferents and/or central N-methyl-d-aspartic acid (NMDA) receptors. Recordings were made from CCK-sensitive RVLM presympathetic vasomotor neurons in halothane-a...

In this study, we examined the acute anticonvulsant spectrum of (1) dizocilpine (0.03-3 mg/kg), CGS 19755 (1-10 mg/kg), and 7-chlorokynurenic acid (1-100 nmol) (NMDA receptor/ionophore complex antagonists); (2) muscimol (0.1-10 nmol; direct GABA(A) agonist); (3) YM90K (3-10 mg/kg; AMPA receptor antagonist); and (4) diazepam (2 and 5 mg/kg) and carbamazepine (5 and 20 mg/kg), two standard antico...