N. Subhedar et al., ACTIVATION OF HYPOTHALAMIC NEURONS BY INTRAOVARIAN PRESSURE SIGNALS IN A TELEOST FISH, CLARIAS-BATRACHUS - ROLE OF MECHANOSENSITIVE CHANNELS, Brain, behavior and evolution, 47(4), 1996, pp. 179-184
Application of intraovarian pressure is known to trigger profound cyto
morphological changes in the neurosecretory cells of nucleus preopticu
s in the teleost Clarias batrachus. These findings indicate the presen
ce of stretch receptors in the ovaries, perhaps equipped with mechanos
ensitive channels that transduce the stretch signals to be transmitted
to the brain. To test the occurrence of the mechanosensitive channels
in the ovaries, we administered a range of pharmacological agents (li
gnocaine, quinidine, tetraethylammonium chloride, ethylenediaminetetra
acetic acid and gadolinium) known to block the mechanosensitive ion ch
annels, in the ovarian lumen prior to the administration of the intrao
varian pressure. Pretreatment with the above agents inhibited the resp
onse by the nucleus preopticus neurosecretory cells to intraovarian pr
essure. The results suggest the occurrence of the mechanosensitive cha
nnels in the ovaries of teleostean fishes. In terms of function we spe
culate that the stretch sensory system and the ensuing pathway connect
ing the ovaries with the hypothalamus might play a role in apprising t
he brain of the status of ovarian maturity and in the initiation of th
e spawning reflex.