Involvement of cannabinoid CB1 and CB2 receptor activity in the development of behavioural sensitization to methamphetamine effects in mice.
OBJECTIVE
An increased behavioural response ("behavioural sensitization") to drugs of abuse occurs after repeated treatment. In the present study the possibility of cross-sensitization existence between various cannabinoid receptor ligands--CB1 agonist methanandamide, CB2 agonist JWH 015, and CB1 antagonist AM 251 with methamphetamine was explored.


METHODS
Locomotion in the open field was measured in naive mice and in those pre-treated acutely and repeatedly (for 8 days), respectively, with either vehicle or tested drugs.


RESULTS
Methamphetamine produced significant sensitization to its stimulatory effect on locomotion. Methanandamide pre-treatment elicited cross-sensitization to methamphetamine effect, whereas pre-treatment with JWH 015 did not. Combined pre-treatment with methamphetamine+AM 251 suppressed sensitization to methamphetamine.


CONCLUSIONS
These results suggest that the activity of the endocannabinoid system is involved in the neuronal circuitry underlying the development of sensitization to methamphetamine.
Landa
Leos
L
Masaryk University, Faculty of Medicine, Department of Pharmacology, Brno, Czech Republic. landa@med.muni.cz
Sulcova
Alexandra
A
Slais
Karel
K
D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D051379:Mice; D008813:Mice, Inbred ICR; D009043:Motor Activity / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D043884:Receptor, Cannabinoid, CB1 / Q000187:drug effects*; D043885:Receptor, Cannabinoid, CB2 / Q000187:drug effects*; D013268:Stimulation, Chemical
D001095:Arachidonic Acids; D000697:Central Nervous System Stimulants; D007211:Indoles; D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; D043885:Receptor, Cannabinoid, CB2; C088155:methanandamide; C103505:AM 251; D008694:Methamphetamine; C402944:JHW 015