Open Access

ARTICLE

Single-channel response of hamster oocytes to fertilization with homologous spermatozoa

by LEONOR M.E. ITUARTE*, TERESA B. VIERA*, TEOBALDO A. SALDEÑA*, JUAN C. DE ROSAS**, MABEL FÓSCOLO**, JORGE E.

* Área de Física Biológica, Departamento de Morfofisiología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Casilla de Correo 33, 5500 Mendoza, Argentina.
** Instituto de Histología y Embriología «Dr. Mario H. Burgos», Departamento de Morfofisiología, CONICET-Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Casilla de Correo 56, 5500 Mendoza, Argentina.
Address correspondence to: Dr. Fernando D. Saraví. Area de Física Biológica, Departamento de Morfofisiología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo. Casilla de Correo 33, (5500) Mendoza, ARGENTINA. Fax: (+54-261) 420 3288. E-mail: synerges@yahoo.com.ar

BIOCELL 2006, 30(1), 43-49. https://doi.org/10.32604/biocell.2006.30.043

Abstract

Electrophysiological events occur early after fertilization, along with changes in intracellular Ca²⁺ concentration . Passive electrical parameters were determined in golden hamster oocytes by whole cell patch-clamp method. In separate experiments the effect of 4-aminopyridine on resting oocytes was tested. The single-channel patch clamp configuration was employed to assess the electrical response to fertilization with homologous sperm. Structure of oocytes submitted to patch clamp was evaluated with scanning electron microscopy and found to be preserved.
Oocyte diameter was 70.2 ± 2.2 µm; their resting parameters were: membrane potential 23.8 ± 0.8 mV; total membrane specific resistance 519.1 ± 94.6 Ω.cm² , and specific capacity 0.99 ± 0.03 µF.cm^-2. Total membrane current was decreased by 42 % by 4-aminopyridine.
Control oocytes and oocytes exposed to sperm differed in their membrane currents in response to a voltage ramp clamping membrane potential from – 100 mV to + 100 mV. In both cases, currents were largest at the most negative potentials, but sperm-exposed oocytes had larger currents. Additionally, while in control oocytes the current was inward at negative potentials but outward at positive potentials, in the presence of spermatozoa oocytes was inward within the whole voltage range tested. This latter current may represent Ca²⁺ entry.

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