Differential effects of nitric oxide synthase inhibitor, 7-nitroindazole, on discriminative stimulus and somatic effects of naloxone in morphine-dependent rats. |
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Authors: | I O Medvedev O A Dravolina A Y Bespalov |
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Affiliation: | Laboratory of Behavioral Pharmacology, Valdman Institute of Pharmacology, Pavlov Medical University, St. Petersburg, Russia. |
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Abstract: | Our previous report suggested that antagonists acting at NMDA receptors attenuate discriminative stimulus effects of naloxone in morphine dependent rats. Nitric oxide (NO) is a putative second messenger which mediates NMDA receptor activation. The present study evaluated behavioral effects of NO synthase inhibitor, 7-nitroindazole in morphine-dependent rats trained to discriminate 0.1 mg/kg naloxone from saline. 7-Nitroindazole did not significantly affect naloxone's discriminative stimulus effects but decreased naloxone-induced weight loss and abolished expression of several withdrawal signs--diarrhea, scream on touch, tremor and 'wet dog'-like shaking suggesting different mechanisms for subjective and somatic components of opioid withdrawal. |
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