Tissue Catecholamines in Rana Tigrina and Effects of Reserpine

Abstract

Reserpine depletes tissue catecholamine contents (CAs) in mammals (1, 2) but may (3, 4, 5) or may not (6) affect the CA stores of cold-blooded animals such as the turtle, frog and toad. Doses as high as 50 mg/kg for 3 days failed to decrease toad tissue CAs (6), which were, however, reported to be sensitive to much lower doses if the ambient temperature was high (7). However, no reference to the effect of reserpine in Rana tigrina, the common Indian species, is available.Adult frogs (Rana tigrina) of either sex weighing 100 to 200 g were used. Reserpine was administered in doses of 25 mg/kg/day given i.p. for three days. The control animals were administered 0.65 NaCl (frog saline) solution in proportionate doses. The animals during drug treatment were kept in moist-base cages at an ambient temperature of 32 to 39°C during May and June. The animals were caudally pithed and tissues were removed 24 hr after the last injection. The adrenaline, noradrenaline and dopamine estimations were carried out in peripheral (whole heart) and central (whole brain) tissue using an Aminco-Bowman spectrophoto-fluorometer as described earlier (8).