REASSESSMENT OF AEROBIC METABOLISM IN AMPHIBIANS DURING ACTIVITY

Activity oxygen consumption rates ((Formula presented.) max) were determined for a variety of amphibians using both electrical and manual stimulation to elicit and maintain activity. The suitability of manometric measurement of(Formula presented.) max was also evaluated. (Formula presented.) max (units, ml/g·h) for three minute activity periods induced by manual stimulation were: Hylaregilla, 1.06±0.10; Hyla cadaverina, 1.25±0.14; Batrachoseps attenuatus, 0.82±0.08; Ensatina eschscholtzi, 0.37±0.6; and Aneides lugubris, 0.70±0.25.(Formula presented.) max was 4 to 6 times greater than previously reported values. In all species,(Formula presented.) during activity was greater than(Formula presented.) during recovery (Tables 1, 2). (Formula presented.) in burst activity (3 min) is about 20% greater than(Formula presented.) in sustained activity (30 min) in Rana pipiens (Fig. 1). VO2max was 3 times greater than previously reported values. Electrical stimulation can lead to physiological impairment of aerobic metabolism as evidenced by a decline in(Formula presented.) with increasing stimulus duration and frequency (Table 1). Electrical stimulation can also lead to errors in(Formula presented.) as a result of electrolytic gas generation (Fig. 2). Manometric measurement of(Formula presented.) can seriously underestimate actual oxygen consumption rates because of temperature transients, resulting from both biological and electrical heat production (Fig. 2). Temperature transients also lead to an apparent delayed development of(Formula presented.) after the activity about. © 1979, Springer-Verlag. All rights reserved.