Chronic benzylpiperazine (BZP) exposure produces behavioral sensitization and cross-sensitization to methamphetamine (MA).
BACKGROUND
Like other psychostimulant drugs, acute exposure to benzylpiperazine (BZP) increases dopaminergic neurotransmission, producing hyperactivity and stereotypy. The consequences of repeated BZP exposure have not however been investigated. The effects of acute and repeated BZP and methamphetamine (MA) exposure on locomotor activity and stereotypy were measured in order to determine whether there was sensitization and cross-sensitization between these two psychostimulant drugs.


METHODS
The effects of acute treatment with MA (0.0, 0.5, 1.0 and 2.0 mg/kg, intraperitoneal (IP)) or BZP (0.0, 5.0, 10.0, 20.0 and 40.0 mg/kg, IP) on locomotor activity and stereotypy were determined. Effects of repeated exposure were determined in other groups that received five daily injections of 2.0 mg/kg MA, 20.0 mg/kg BZP or vehicle. Following a 2-day withdrawal period, rats from each treatment group received either a low dose MA (0.5 mg/kg) or BZP (10.0 mg/kg).


RESULTS
MA and BZP produced dose-dependent hyperactivity and stereotypy. Repeated MA and BZP resulted in a potentiated locomotor but not stereotypy response. Following the withdrawal period, MA pretreated rats exhibited a sensitized locomotor and stereotypy response to the low dose MA and a conditioned response to saline. BZP pretreated rats also demonstrated a sensitized locomotor response to the low dose of BZP and MA.


CONCLUSIONS
The present findings indicate that repeated exposure to BZP results in sensitization and cross-sensitization to MA.
Brennan
K
K
Institute of Environmental Science and Research (ESR), School of Psychology, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand.
Johnstone
A
A
Fitzmaurice
P
P
Lea
R
R
Schenk
S
S
D000818:Animals; D004298:Dopamine / Q000502:physiology; D004334:Drug Administration Schedule; D007114:Immunization; D008297:Male; D008694:Methamphetamine / Q000633:toxicity*; D023421:Models, Animal; D009043:Motor Activity / Q000187:drug effects*; D010879:Piperazines / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013239:Stereotyped Behavior / Q000187:drug effects*; D013997:Time Factors
C461488:N-benzylpiperazine; D010879:Piperazines; D008694:Methamphetamine; D004298:Dopamine