Xj. Xu et Ef. Domino, CROSS-SENSITIZATION BETWEEN PHENCYCLIDINE AND (-)PENTAZOCINE BUT NOT (+)PENTAZOCINE, Pharmacology, biochemistry and behavior, 56(2), 1997, pp. 205-210
Repeated administration of psychomotor stimulants such as amphetamine
and cocaine, and psychotomimetics such as phencyclidine, produce progr
essively enhanced behavioral effects, a phenomenon known as behavioral
sensitization. Little is known about the effects of repeated treatmen
t with sigma ligands on locomotor activity. The present research deter
mined the psychomotor stimulant effects of the sigma ligand (+)pentazo
cine and its enantiomer; and investigated whether reciprocal cross-sen
sitization occurs between them and PCP-induced locomotor activity and
ambulation. Adult female Sprague-Dawley rats were used. Total locomoto
r activity and ambulation were assessed with an automated photoelectri
c system. Acute (+) or (-)pentazocine given IP produced slight but ins
ignificant locomotor stimulant effects. Repeated administration of (+)
pentazocine failed to produce behavioral sensitization. However, four
repeated injections of (-)pentazocine or PCP produced behavioral sensi
tization. (-)Pentazocine sensitized rats showed cross-sensitization to
PCP-induced locomotion and ambulation. Furthermore, PCP sensitized ra
ts showed cross-sensitization to (-)pentazocine-induced locomotion and
ambulation. These findings suggest that (+) and (-)pentazocine act at
different receptor sites. (-)Pentazocine is more similar to PCP in pr
oducing locomotor stimulant effects. Copyright (C) 1997 Elsevier Scien
ce Inc.