ISSN:
1432-2072
Keywords:
Drug discrimination
;
ϰ opioids
;
Ethylketazocine
;
Cyclazocine
;
Nalorphine
;
Naltrexone
;
Macaque monkeys
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract dl-Ethylketazocine (EKC, 0.01 mg/kg) and saline were established as discriminative stimuli for food-maintained responding in macaque monkeys. Thirty consecutive presses on a right or left lever were reinforced with food, contingent on whether EKC or saline were administered before the session. For tests of antagonism, naltrexone, or UM 979 [(l)-5,9-alpha-dimethyl-2-(3-furylmethyl)-2′-hydroxy-6,7-benzomorphan] was administered concomitantly with EKC,dl-cyclazocine, or nalorphine. Both antagonists blocked completely the EKC discriminative stimulus. The antagonism of the stimulus and rate-altering effects of EKC was surmountable, with considerable intersubject variability in the magnitude of the EKC dose increase required to overcome the blockade. Cyclazocine and nalophine, mixed agonist-antagonist opioids that share stimulus properties with EKC, were also susceptible to antagonism. Naltrexone antagonized completely the EKC stimulus effects of nalorphine; naltrexone and UM 979 antagonized completely the EKC stimulus effects of cyclazocine. Naltrexone antagonism of the cyclazocine stimulus was not surmountable, due to a lack of antagonism of the rate-decreasing effects of high cyclazocine doses.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00555213
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