Effects of agonists of melanocortin receptors MC3Rand MC4R on components of sexual behavior of male rats reared in condition of chronic social isolation

BACKGROUND: Melanocortins, including -melanocyte stimulating hormone (MSH), MSH, and adrenocorticotropic hormone, are products of the polypeptide proopiomelanocortin. These bind to five different melanocortin receptors (MC1R, MC2R, MC3R, MC4R, MC5R) with affinities. Because MC3R MC4R major types expressed in brain, these two can mediate behavioral effects melanocortins.
 AIM: To clear role sexual behavior male rats after social isolation from relatives.
 MATERIALS AND METHODS: In present study, 40 naive Wistar divided into 4 groups, 3 which were grown complete partial sensory isolation, received saline, PT-141 (MC3R/MC4R agonist) a dose 0.3 g intraperitoneally, THIQ (MC4R 0.1 intranasally. Behavioral registered cage unreachable reinforcement female estrus phase, separated by transparent perforated barrier, was kept for 10 minutes under red light. Blood samples taken 30 administration tail vein. Testosterone concentrations measured ELISA.
 RESULTS: Social had no significant effect on latent time before trying reach but decreased spent near female. Isolated animals did not show genital grooming acts during experiment. approach female, increased cage, stimulated grooming. At same time, cage. reduced testosterone levels more than twice compared controls. The concentration.
 CONCLUSIONS: results confirm depressing chronic stress motivation demonstrate roles MC3R/MC4R realization behavior.