@entity1286 -dependent @entity35 can be trained to discriminate between s.c. injections of saline and 0.1 mg/kg of @entity836 . The discriminative effects of @entity836 , measured by the number of trials completed on the @entity836 -appropriate choice lever in a 20-trial avoidance paradigm, derive from stimuli associated with @entity1286 withdrawal. Opiate and nonopiate drugs were injected s.c. and examined for their ability to block @entity836 -induced discriminative effects and loss of body weight in @entity1286 -dependent @entity35 . Seven opiates blocked dose dependently the discriminative effects of @entity836 and loss of body weight. Potency ranged from @entity3575 (330 X @entity1286 ) to @entity6882 (less than 1 X @entity1286 ); effects were stereoselective for levorotatory isomers. @entity3062 , an opiate that does not readily enter the brain, blocked loss of body weight but not discriminative effects, suggesting that discriminative effects are mediated centrally. Nonopiate behavioral depressants, @entity3175 , @entity1767 and @entity4485 , did not substantially affect either dependent variable, but @entity1338 (0.01-1.0 mg/kg) blocked discriminative effects of @entity836 partially and @entity353 completely. The blockade by @entity1286 (30 mg/kg) of @entity836 -induced discriminative effects and @entity353 was surmounted by increasing the dose of @entity836 whereas the blockade by @entity1338 (0.1 mg/kg) was not. Thus, blockade by opiates of effects of @entity836 appears to be due to a competitive interaction at the mu opioid receptor; @entity1338 has a different mechanism of action. This discrimination paradigm may afford a specific animal model for studying fundamental processes underlying physical dependence on opiates and for evaluating novel pharmacologic approaches for treating opiate withdrawal in @entity1 .

Discriminative stimulus effects of XXXX withdrawal in the dependent @entity35 : suppression by opiate and nonopiate drugs.

@entity4485 :: ('MESH:D010424', 'Chemical') :: ['pentobarbital'] @entity836 :: ('MESH:D009271', 'Chemical') :: ['naltrexone'] @entity1 :: ('9606', 'Species') :: ['humans'] @entity3175 :: ('MESH:D003975', 'Chemical') :: ['diazepam'] @entity1338 :: ('MESH:D003000', 'Chemical') :: ['clonidine'] @entity353 :: ('MESH:D015431', 'Disease') :: ['weight loss'] @entity6882 :: ('MESH:D008614', 'Chemical') :: ['meperidine'] @entity1286 :: ('MESH:D009020', 'Chemical') :: ['morphine', 'Morphine'] @entity1767 :: ('MESH:D006220', 'Chemical') :: ['haloperidol'] @entity35 :: ('10116', 'Species') :: ['rats'] @entity3575 :: ('MESH:D005283', 'Chemical') :: ['fentanyl'] @entity3062 :: ('MESH:D008139', 'Chemical') :: ['Loperamide']
@entity1286 :: (MESH:D009020,Chemical) :: ['morphine']
