Effects of temperature on tadpole hearts in vitro.

INTRODUCTION The temperatures currently used for amphibian cell and tissue culture appear to range from 26 °C (Seto, 1964) to 18 °C (Shah, 1964). The experiments of N. G. Stephenson & Tomkins (1964), in which Pseudophryne tadpole humeri and femora transplanted to chick chorioallantoic membranes at 38 °C showed definite growth, suggested the possible advantage of culturing other amphibian tissues at temperatures above 26 °C. The present study has therefore been carried out in an attempt to establish more precisely the optimal and maximal conditions for amphibian cell and organ culture. Whole hearts of tadpoles of the Leptodactylid frog, Limnodynastes peroni (Dumeril & Bibron) were cultured at a series of temperatures ranging from 5 to 37°C for a period of at least 1 week. Although the short-term behaviour of an isolated, adult frog's heart in Ringer's solution in relation to increased temperature is known (Mitchell, 1956), only incidental observations have been recorded with regard to temperature effects on rate of beat of cultured amphibian heart fragments (Johnson, 1915; Morosow, 1929) or embryonic heart rudiments (Stohr, 1924). By using whole tadpole hearts in culture it has been possible to observe the effects of different temperatures on organ function and maintenance, as indicated by heart beat, as well as on cell outgrowth.