title: The membrane potential of the Japanese quail's oviductal smooth muscle during ovum transport.
abstract: Previously it has been shown that in the quail's oviductal smooth muscle there exists coordinated electrical and mechanical activity. It is not known how the contractions are regulated; the oviduct probably functions as a stretch receptor and the mechanical stimulus is produced by the ovum itself. The cellular basis for stretch-induced contractions is not known. In strips (n = 8) from the magnum, stretches of 50% changed the membrane potential. Compared with the resting length L0 (= 100%), stretches to 150% and 200% significantly (p less than 0.001) hyperpolarized the membrane potential. Analyses of variance, however, revealed that at the length 150% both the level of stretch and single experiments differed significantly in relation to the membrane potential: F = 7.1, p less than 0.5; F = 14.6, p less than 0.01, respectively. At the length 200%, there were highly significant differences between the groups 100% and 200% (F = 36.3, p less than 0.001) but the differences could be explained by the highly significant (F = 13.9, p less than 0.001) interaction. Membrane potential measured from isolated, intact oviducts (n = 7) which had ovum in the magnum was significantly depolarized by 8-9 mV on the region over the ovum. On the other hand, the membrane potentials were the same in the different segments of the oviduct which did not contain an ovum: 52 mV.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D003370:Coturnix; D005260:Female; D008465:Mechanoreceptors / Q000502:physiology; D008564:Membrane Potentials; D009130:Muscle, Smooth / Q000502:physiology*; D010057:Oviducts / Q000502:physiology*; D010066:Ovum Transport