Endocrinology, Vol 110, 1320-1324, Copyright © 1982 by Endocrine Society

ARTICLES

Release of E prostaglandins into the cerebrospinal fluid and its inhibition by melatonin after cervical stimulation in the rabbit

CM Leach, JA Reynoldson and GD Thorburn

The release of the E type of prostaglandin (PGE) into the cerebrospinal fluid of mature female rabbits was studied using an indwelling catheter in the cisterna magna. The cervix of the rabbit was stimulated 5 min after the central injection of either vehicle or melatonin solution. PGE was measured by RIA, and in unstimulated animals, the level of PGE remained steady at about 4 ng/ml. After stimulation of the cervix of control rabbits, PGE levels rose by 31 ng/ml 40--70 min after the initiation of stimulation in those animals which subsequently ovulated. PGE levels rose by only 15 ng/ml 70--115 min after stimulation in those rabbits which did not ovulate. In the melatonin-treated rabbits, PGE levels remained close to those in unstimulated controls, and ovulation did not occur. Thus, stimulation of the cervix of the rabbit produces a rise in PGE levels in cerebrospinal fluid. This endogenous PGE surge may, in turn, cause the release of LHRH and LH and induce ovulation if levels exceed a critical threshold. A weaker stimulus leads to only a smaller surge of PGE, insufficient to cause ovulation. Melatonin blocked the stimulation-induced rise in cerebrospinal fluid PGE levels and ovulation, and appears to exert its antigonadotropic activity in the rabbit by the inhibition of central PGE synthesis.

This article has been cited by other articles:

				M F P Peres, M S. del Rio, M L V Seabra, S Tufik, J Abucham, J Cipolla-Neto, S D Silberstein, and E Zukerman Hypothalamic involvement in chronic migraine J. Neurol. Neurosurg. Psychiatry, December 1, 2001; 71(6): 747 - 751. [Abstract] [Full Text] [PDF]