STRETCH SENSORY OVARIAN-PREOPTIC PATHWAY IN THE TELEOST, CLARIAS-BATRACHUS (LINN) - TRANSECTION STUDIES

Application of intraovarian pressure (IOP), coupled with placement of discrete lesions, has been employed to study the organization of the p ressure excitable ovarian-preoptic pathway in a teleost, Clarias batra chus. While bilateral administration of the IOP triggered stimulatory changes in the nucleus preopticus (NPO), they were abolished if the IO P administration was preceded by the bilateral transection at the leve l of 1) foramen magnum, 2) spinal cord at the level of 13th vertebra, 3) dorsal spinal nerve roots between the levels of 13th and 21st verte brae, and 4) at the junction between the common oviduct and the body w all. On the other hand, bilateral sectioning of the anterior mesovariu m, the vagi, or the spinal cord at the level of 21st vertebra had no e ffect. Unilateral administration of the IOP triggered bilateral change s in the NPO. It seems that the stretch receptors in the ovarian wall give rise to processes that proceed along the margin of the oviduct an d enter the spinal cord via the dorsal nerve roots between 13th and 21 st vertebrae. Thereafter, the pathway seems to ascend over the spinal cord and impinge on the ipsilateral as well as contralateral NPO. (C) 1993 Wiley-Liss, Inc.