PHENYTOIN AND PHENOBARBITAL - A COMPARISON OF THEIR STATE-DEPENDENT EFFECTS

Citation
Kb. Kumar et al., PHENYTOIN AND PHENOBARBITAL - A COMPARISON OF THEIR STATE-DEPENDENT EFFECTS, Pharmacology, biochemistry and behavior, 47(4), 1994, pp. 951-956
Citations number
33
Categorie Soggetti
Pharmacology & Pharmacy
ISSN journal
00913057
Volume
47
Issue
4
Year of publication
1994
Pages
951 - 956
Database
ISI
SICI code
0091-3057(1994)47:4<951:PAP-AC>2.0.ZU;2-O
Abstract
Two commonly used antiepileptic drugs, phenytoin sodium and phenobarbi tal sodium, were investigated for state-dependency effects at differen t doses. Male Wistar strain rats trained to a criterion in an inhibito ry avoidance task and a food-motivated T-maze task under varying drug and nondrug states were subjected to retention tests 24 and 48 h, resp ectively, following acquisition. The treatment instituted at the time of retrieval was either the same as, or different from, that used duri ng training. The results indicated that phenytoin produced state-depen dency effects at test doses of 20, 40, and 60 mg/kg in the avoidance t ask and at test dose of 20 mg/kg in the T-maze task experiments. These state-specific effects were comparable to those of phenobarbital sodi um (5 and 10 mg/kg). The reinstitution of the drug state in an additio nal test session produced approximately equal and significant recovery of conditioned responses in the T-maze paradigm both in phenytoin and phenobarbital groups. These results demonstrate, for the first time, the ability of phenytoin to produce state-dependency effects in a patt ern similar to that observed with a widely studied compound such as ph enobarbital. Overall, the data provide no support for the view that th e degree of discriminability of a drug is an indicator of potential st ate-dependency effects and is restricted only to the dosage high enoug h to produce noticeable intoxication.