Brain research bulletin
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Brain research bulletin · Sep 2003
LHRH release depends on Locus Coeruleus noradrenergic inputs to the medial preoptic area and median eminence.
We tested the hypothesis that Locus Coeruleus (LC) inputs to the medial preoptic area (MPOA) and median eminence (ME) are essential for gonadotropin release. Proestrus and ovariectomized (OVX) rats were decapitated at 16:00 h. LC electrolytic lesion was performed at 11:00 h during proestrus and 24h before decapitation in OVX rats. ⋯ In OVX rats, there was an increase at 15:00 h in the LC and a decrease at 17:00 h in both areas. The number of FOS-ir neurons was lower in OVX than in proestrus animals. Thus, LC (1) is responsible, at least in part, for gonadotropin release through the activation of LHRH neurons, (2) is more closely related to the positive than the negative feedback, and (3) seems to show an intrinsic cyclic activity which is amplified by ovarian steroids.