Meeting Abstract

P2.93  Jan. 5  Spontaneous Ovarian Contractions in Teleosts MARINO, C.L.*; JENSEN, B.H.; The College of Saint Rose, Albany; The College of Saint Rose, Albany jensenb@strose.edu

Previous work has determined that the ovaries of many species of teleost fish contract spontaneously. In the best-studied example, the semilunar spawning mummichog (Fundulus heteroclitus), the reproductive status of the fish appears to determines the frequency, duration and amplitude of these spontaneous ovarian contractions. To date, the existence of these contractions has been demonstrated in fish with semilunar or annual reproductive patterns, but fish with a daily spawning pattern have yet to be examined. Further, the physiological purpose – if one exists – of these contractions is still uncertain. The purpose of this study was to develop a technique suitable for quantifying ovarian contractions in the diminutive teleost Danio rerio (zebrafish) and to determine the extent to which their ovaries contract and are affected by their daily reproductive cycle. Mature female zebrafish were sacrificed by submersion in carbonated water followed by decapitation. The ovaries were removed, and maintained in a smooth muscle bath containing teleost Ringer�s at 20�C. Ovarian contractions were measured using a CB scientifics iWorx 214 data acquisition system and an FT302 dual range force transducer. Manual calibration was used to determine the accuracy of the two-point calibration function. At the termination of each experiment, acetylcholine (ACh) was added to the smooth muscle bath to induce contraction. Zebrafish ovaries did produce spontaneous myogenic contractions with a duration of approximately 60s and an amplitude of approximately 70% of maximum induced contraction. These contractions are similar in nature to those found in other teleosts. We are currently working to establish whether there is a diel pattern in the frequency, duration or amplitude of the contractions.