Patterns of electrical propagation in the intact pregnant guinea pig uterus

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2008-03, Vol.294 (3), p.R919-R928
• Main Authors: Lammers, Wim J. E. P, Mirghani, H, Stephen, B, Dhanasekaran, S, Wahab, A, Al Sultan, M. A. H, Abazer, F
• Format: Article
• Language: English
• Subjects: Animals; Anisotropy; Electrodes; Electrodes, Implanted; Electromyography; Electrophysiology; Female; Guinea Pigs; In Vitro Techniques; Myometrium - anatomy & histology; Myometrium - physiology; Pregnancy; Pregnancy, Animal - physiology; Reproductive system; Rodents; Studies; Uterine Contraction - physiology; Uterus - anatomy & histology; Uterus - physiology
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.00704.2007

Departments of 1 Physiology, 2 Obstetrics and Gynecology, 3 Pharmacology, and 4 Medical Education, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates Submitted 1 October 2007 ; accepted in final form 20 November 2007 Previous studies have reported on propagation of individual spikes in isolated segments of the pregnant uterus, but there is no information on patterns of spike propagation in the intact organ. There is also no information on propagation of myometrial burst. The aim of this study was to record, at high resolution, patterns of propagation of electrical activities in the pregnant uterus. Sixteen timed-pregnant guinea pigs were euthanized at term, and their uteruses isolated. Fetuses were removed and replaced by an equal amount of Tyrode. A 240-electrode array was positioned at various locations along the organ, all signals were recorded simultaneously, and the electrical propagations were reconstructed. In the intact pregnant uterus at term, spikes propagated with high velocity in longitudinal (6.8 ± 2.4 cm/s) and slower velocity in circular direction (2.8 ± 1.0 cm/s; P < 0.01). Direction of propagation and frequency of activity were highly variable but showed similar patterns at the ovary or cervical end and along the anterior, posterior, and antimesometrial borders. Along mesometrium, spike propagation was sparse and fractionated. Migration of burst (0.6 ± 0.4 cm/s) was significantly much slower than that of individual spikes ( P < 0.001). Initial burst activity was located at variable locations along the ovarial end of the antimesometrial border, while the latest excitation occurred at the cervical end (1.2 ± 0.9 min). In conclusion, high resolution electrical mapping of the intact pregnant uterus reveals fundamental properties in spatial and temporal patterns of spike and burst propagation that determine the contraction of the organ. spikes; myometrial burst migration Address for reprint requests and other correspondence: W. J. E. P. Lammers, Dept. of Physiology, Faculty of Medicine and Health Sciences, P.O. Box 17666, Al Ain, United Arab Emirates (e-mail: wlammers{at}smoothmap.org )