Differential effects of nitric oxide synthase inhibitor, 7-nitroindazole, on discriminative stimulus and somatic effects of naloxone in morphine-dependent rats
Io. Medvedev et al., Differential effects of nitric oxide synthase inhibitor, 7-nitroindazole, on discriminative stimulus and somatic effects of naloxone in morphine-dependent rats, EUR J PHARM, 377(2-3), 1999, pp. 183-186
Our previous report suggested that antagonists acting at NMDA receptors att
enuate discriminative stimulus effects of naloxone in morphine dependent ra
ts. Nitric oxide (NO) is a putative second messenger which mediates NMDA re
ceptor activation. The present study evaluated behavioral effects of NO syn
thase inhibitor, 7-nitroindazole in morphine-dependent rats trained to disc
riminate 0.1 mg/kg naloxone from saline. 7-Nitroindazole did not significan
tly affect naloxone's discriminative stimulus effects but decreased naloxon
e-induced weight loss and abolished expression of several withdrawal signs
- diarrhea, scream on touch, tremor and 'wet dog'-like shaking suggesting d
ifferent mechanisms for subjective and somatic components of opioid withdra
wal. (C) 1999 Elsevier Science B.V. All rights reserved.