Chronic treatment with CP 55,940 during the peri-adolescent period differentially affects the behavioural responses of male and female rats in adulthood.
BACKGROUND
Despite the increasing use of cannabis among adolescents, there is scarce information about the long-term effects of cannabinoid receptor agonists in appropriate animal models.


OBJECTIVE
We aimed to investigate the behavioural features of adult male and female Wistar rats that had been exposed to a chronic treatment with the cannabinoid receptor agonist CP 55,940 (CP) during the juvenile period.


METHODS
CP (0.4 mg/kg i.p.) or its corresponding vehicle was administered once daily, from day 35 to day 45. In adulthood, the animals were tested in the holeboard, the open field and the elevated plus-maze, under different stress (illumination) conditions. After a resting period, the serum corticosterone levels (radioimmunoassay) of the animals were measured. The effects of CP on food intake and somatic growth were monitored throughout the experimental period.


RESULTS
The CP treatment induced significant sex-dependent effects on holeboard activity, as well as a decrease in the level of emotionality/anxiety in the open field and in the plus-maze. The animals receiving CP also showed diminished food intake and body weights during the treatment period, but both parameters recovered normal values during the period after treatment. No significant effect of the CP treatment on corticosterone levels was found.


CONCLUSIONS
The results demonstrate that chronic administration of CP during the peri-adolescent period resulted in marked behavioural effects in adulthood. The nature of these effects depended on the sex of the animals and on the specific behavioural test. The possible neurobiological substrates underlying the effects of CP are discussed.
Biscaia
Miguel
M
Departamento de Psicobiología de la UNED, Madrid, Spain.
Marín
Susana
S
Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense, 28040, Madrid, Spain.
Fernández
Beatriz
B
Departamento de Psicobiología de la UNED, Madrid, Spain.
Marco
Eva M
EM
Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense, 28040, Madrid, Spain.
Rubio
Marina
M
Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense, 28040, Madrid, Spain.
Guaza
Carmen
C
Instituto Cajal, Madrid, Spain.
Ambrosio
Emilio
E
Departamento de Psicobiología de la UNED, Madrid, Spain.
Viveros
Maria Paz
MP
Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense, 28040, Madrid, Spain. pazviver@bio.ucm.es.
D000700:Analgesics / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003345:Corticosterone / Q000097:blood*; D003511:Cyclohexanols / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects; D005260:Female; D006128:Growth; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012737:Sex Factors; D013997:Time Factors
D000700:Analgesics; D003511:Cyclohexanols; C054649:3-(2-hydroxy-4-(1,1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol; D003345:Corticosterone