Decreased rodent sexual receptivity after lindane

Female rats were injected on the morning of proestrus with 25, 33, 50 or 75 mg/kg lindane or with 1, 2, 2.5 or 3 mg/kg picrotoxin. That evening, females were examined for lordosis behavior with a sexually experienced male. Picrotoxin had no inhibitory effects on lordosis behavior. There was a dose-dependent reduction in sexual receptivity (lordosis to mount behavior) with increasing doses of lindane. At none of the tested doses of lindane was there a total absence of lordosis behavior. However, lindane animals experienced a greater number of mounts before the first lordosis response was observed. Lindane-treated females may have required a greater amount of sensory stimulation to elicit the lordosis reflex. A majority of the lindane-treated females also failed to exhibit proceptive behavior (darting and hopping) during the mating test. The inhibitory effects of lindane on lordosis behavior are similar to previous reports of the effects of another chlorinated pesticide, chlordecone, on female sexual receptivity. Both compounds disrupt central nervous system neurotransmitters and this may account for their common attenuation of sexual behavior. Since both lindane and picrotoxin are recognized for their disturbance of the GABAergic system, these findings suggest that lindane's inhibition of sexual receptivity may not be mediated through its GABAergic action.