Inherent rhythmicity and interstitial cells of Cajal in a frog vein.
Interstitial cells of Cajal are responsible for rhythmic contractions of the musculature of the gastrointestinal tract and blood vessels.The existence of these cells and spontaneous rhythmicity were noticed in amphibian vein and the findings are reported in this paper.The postcaval vein was identified in the frog, Rana tigrina and was perfused with amphibian Ringer solution after isolation.Contractile activity was recorded through a tension transducer connected to a polygraph.The isolated postcaval vein showed spontaneous rhythmic activity. Addition of cold Ringer solution decreased, while warm Ringer increased, the rate of contraction. Adrenaline caused inhibition of rhythmic activity at a dosage that increased the rate of isolated sinus venosus.Sections of the postcaval vein,when stained supravitally with methylene blue, showed the presence of interstitial cells of Cajal. Photic stimulation of the vein in the presence of methylene blue led to a significant decrease in the rate of spontaneous beating of the vein.These findings indicate that the postcaval vein of frog is capable of inherent rhythmcity, which is dependent on the interstitial cells of Cajal but is independent of the sinus venosus.
Ghose
Dipanwita
D
Department of Physiology,Kasturba Medical College, Manipal, 576104, India.
Jose
Lingu
L
Manjunatha
S
S
Rao
Muddanna S
MS
Rao
J Prakasa
JP
D000818:Animals; D007552:Isotonic Solutions; D008027:Light; D008751:Methylene Blue / Q000494:pharmacology; D010507:Periodicity; D011898:Ranidae / Q000502:physiology; D000077331:Ringer's Solution; D013696:Temperature; D014680:Veins / Q000166:cytology* / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects
D007552:Isotonic Solutions; D000077331:Ringer's Solution; D008751:Methylene Blue