PARENT SESSION
Follicular Development

TRANSMISSION OF PURINERGIC-EVOKED ELECTRICAL SIGNALS FROM CUMULUS CELLS TO THE OOCYTE IN MOUSE.

Garay, Edith¹, Arellano, Rogelio O.¹, ¹

ABSTRACT- The interactions between the germ cell and somatic cells in the follicle provide crucial intercellular communication which is necessary for the complete development of the gamet. In order to study these interactions, we monitored the communication in cumulus cells-enclosed oocytes (CEO) using electrophysiological methods. CEO were dissected from antral follicles of mouse and maintained in culture up to 10 days, until electrical properties were monitored using the two-microelectrodes voltage clamp technique. It is know that purinergic molecules are present in the follicular fluid, and it has been suggested that some of these molecules are involved in oogenesis regulation. Electrophysilogical studies of CEO gave information about the pharmacological characteristics of purinergic receptors present in their membrane and also about the ionic currents activated when they were stimulated. Two different ion currents were elicited by application of ATP or UTP, one was carried mainly by Cl^- while a second one was drive by cations. Both currents were dependent on electrical coupling, and were independent on extracellular Ca⁺⁺. However, only the Cl^- current response depended on increase of intracellular Ca⁺⁺. The pharmacological characteristics of the purinergic receptor, and the detections by PCR of transcripts P2y2 (P2U) receptor subtype from cumulus cells in culture, strongly suggested that this receptor subtype was responsible for the ion currents elicited by ATP in CEO. Supported by CONACyT México 32364-N and PAPIIT-UNAM IN200198

KEY WORDS: Ion currents, membrane receptor, oogenesis