TY - JOUR
T1 - Lack of cross-sensitization of the locomotor effects of morphine in amphetamine-treated ras
AU - Vanderschuren, L.J.M.J.
AU - Schoffelmeer, A.N.M.
AU - Mulder, A.H.
AU - de Vries, T.J.
PY - 1999/10/1
Y1 - 1999/10/1
N2 - Repeated exposure to morphine and amphetamine induces long-lasting sensitization of their psychomotor stimulant properties, whereas pretreatment with morphine causes cross-sensitization of the locomotor effects of amphetamine. Here, we investigated whether pre-exposure to amphetamine also results in cross-sensitization to morphine. Rats pretreated with amphetamine (5 x 2.5 mg/kg, i.p.) displayed neither short-term (3 days post-treatment) nor long-term (3 weeks post-treatment) cross-sensitization of the locomotor effects of morphine (2 or 5 mg/kg, s.c.). Two other amphetamine pretreatment protocols (1 x 5 mg/kg, i.p. and 14 x 2.5 mg/kg, i.p.) also failed to induce cross-sensitization to morphine. In contrast, all amphetamine pretreatment regimens induced sensitization of the locomotor effects of amphetamine (1 mg/kg, i.p.) and pretreatment with morphine (14 x 10 mg/kg, s.c.) induced both short- and long-term sensitization of the locomotor effects of both morphine and amphetamine. These data suggest that the expression of sensitization of the locomotor effects of morphine and amphetamine, at least partially, involves distinct neuroadaptive phenomena. Copyright (C) 1999 American College of Neuropsychopharmacology.
AB - Repeated exposure to morphine and amphetamine induces long-lasting sensitization of their psychomotor stimulant properties, whereas pretreatment with morphine causes cross-sensitization of the locomotor effects of amphetamine. Here, we investigated whether pre-exposure to amphetamine also results in cross-sensitization to morphine. Rats pretreated with amphetamine (5 x 2.5 mg/kg, i.p.) displayed neither short-term (3 days post-treatment) nor long-term (3 weeks post-treatment) cross-sensitization of the locomotor effects of morphine (2 or 5 mg/kg, s.c.). Two other amphetamine pretreatment protocols (1 x 5 mg/kg, i.p. and 14 x 2.5 mg/kg, i.p.) also failed to induce cross-sensitization to morphine. In contrast, all amphetamine pretreatment regimens induced sensitization of the locomotor effects of amphetamine (1 mg/kg, i.p.) and pretreatment with morphine (14 x 10 mg/kg, s.c.) induced both short- and long-term sensitization of the locomotor effects of both morphine and amphetamine. These data suggest that the expression of sensitization of the locomotor effects of morphine and amphetamine, at least partially, involves distinct neuroadaptive phenomena. Copyright (C) 1999 American College of Neuropsychopharmacology.
KW - Amphetamine
KW - Behavioral sensitization
KW - Locomotor activity
KW - Morphine
UR - http://www.scopus.com/inward/record.url?scp=0032879686&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/S0893-133X(99)00051-2
DO - https://doi.org/10.1016/S0893-133X(99)00051-2
M3 - Article
C2 - 10481839
SN - 0893-133X
VL - 21
SP - 550
EP - 559
JO - Neuropsychopharmacology
JF - Neuropsychopharmacology
IS - 4
ER -