Vasotocin-like activity of cerebrospinal fluid induced by habenular lesions in cats.

The cisternal cerebrospinal fluid (CSF) samples, taken at 30, 60, 120 and 180 minutes after multiple electrolitic lesions of lateral habenular (LHB) lesions or of thalamus, performed in urethane anesthetized cats, were assayed for their antidiuretic and hydroosmotic activities before and after trypsine or thioglycollate incubation. LHB but not thalamic lesions, specifically induced the appearance of antidiuretic and hydroosmotic activities at 60 and 120 minutes. The activities decreased under the bioassays sensibilities at 180 minutes. The biological activities of the CSF samples, their ratio as well as their susceptibility to tryptic digestion and thioglycollate incubation suggest that LHB lesions induce the release of a basic peptide with a disulfide bound, indistinguishable from arginine vasotocin (AVT). Since it was previously argued that there is a pineal-habenula circuit with AVT as neuromudulator, it is advanced the hypothesis that LHB lesions interfere with an inhibitory feed-back loop between habenula and the pineal gland.