Pain Reduces Sexual Motivation in Female But Not Male Mice

Reduction of sexual behavior in female but not male mice by inflammatory pain. A, Decreased mounting behavior in a paced mating (F-PM) paradigm when female mice receive zymosan (ZYM) or carrageenan (CARR) injections to the vulva, hind paw, tail, or cheek, compared with uninjected female mice (No Inj.). Bars represent mean ± SEM mounts with (shaded) or without (open) intromissions; n = 7–12 mice/condition. B, Female mice with genital (vulvar; n = 6) or nongenital (combined hind paw, tail, and cheek; n = 23) pain spend less time on the side containing the male in a paced-mating chamber compared with mice receiving uninjected or vehicle injected mice (No Pain; n = 43). Bars represent mean ± SEM time on male side (s). C, No decreases in mounting behavior in an open field (M-OF) when male mice are treated similarly to female mice. Bars as in A; n = 6–10 mice/condition. D, No sex difference in mechanical allodynia produced by hind paw zymosan. Symbols represent mean ± SEM threshold (g) to withdraw from von Frey fibers before (BL) and after (Post-Inj.) bilateral zymosan injection; n = 6 mice/sex. E, No sex difference in facial grimacing produced by hind paw zymosan. Symbols represent mean ± SEM Mouse Grimace Scale (MGS) score before (BL) and after (Post-Inj.) bilateral zymosan injection; n = 4 mice/sex; *p < 0.05, **p < 0.01, ***p < 0.001 compared with vehicle (A, C), No Pain (B), or BL (D, E).