The response of nucleus preopticus neurosecretory cells to ovarian pressure in the teleost, Clarias batrachus (Linn.)

Involvement of corticotropin-releasing factor and adrenocorticotropic hormone in the ovarian maturation, seawater acclimation, and induced spawning of Liza ramada

“…This mild stress may increase the synthesis and the release of CRF-ir cells in the NPO and MO in agreement with the previous report by Haas and George (1988b). Consistently, Subhedar et al (1987) reported that the application of intraovarian low pressure (10 mm Hg) revealed a marked hypertrophy in the neurosecretory cells of the NPO suggesting the existence of a pressure-excitable neural pathway from the ovary capable of eliciting profound cytological changes in the NPO in the teleost Clarias batrachus. Ganesh and Yajurvedi (2002) showed that CRF antagonist attenuates stress-induced inhibition of ovarian follicular and oviductal development in the lizard Mabuya carinata.…”

“…The possible explanation of the observed hypotrophy of CRF-ir cells in the brain during induction of spawning in L. ramada is that after induced spawning by hormonal injection, GSI was increased to the maximum values within 33-64 h (38.4-46.5), i.e., two times higher than those of prespawning females and may cause a high degree of stress in ovulated females. This explanation is supported by previous experiments from Subhedar et al (1987) demonstrating histological and immunohistochemical changes in the neurosecretory cells of the NPO following pressure stimulation of the ovaries in the teleost, C. batrachus. The authors also showed that the application of intraovarian pressure of 10 mm Hg (low pressure) revealed a marked hypertrophy of the cells, while pressures of 20 and 30 mm Hg (high pressure) resulted in hypotrophy and exhaustion of the cells suggesting the existence of a pressure-excitable neural pathway from the ovary capable of eliciting profound cytological changes in the NPO in the teleost C. batrachus.…”

Activation of Hypothalamic Neurons by Intraovarian Pressure Signals in a Teleost Fish, <i>Clams batrachus:</i> Role of Mechanosensitive Channels

“…In Clarias batrachus, nucleus preopticus consists of a paraventricular division extending vertically along the pre optic recess and a supraoptic division located above the optic chiasma fSubhedaret al, I990], The response of both subdivisions of nucleus preopticus to intraovarian pressure of 20 mm Hg magnitude, as revealed by aldehyde I'uchsin staining, has already been described [Subhedar et al, 1987). The morphometric changes in cell diameter and nu clear diameter of the neurons from nucleus preopticus in various treated and control groups are summarized in figure 3.…”

“…The fish of group 1 were not subjected to intraovarian pressure. The Fish of group 2 were given intraovarian pressure, as per the procedure described elsewhere [Subhedar et al" 1987]. Briefly, they were lightly anes thetized by immersion in MS 222. the abdomen was opened length wise.…”