[Calorigenic action of dopamine and dobutamine]

In tests on narcotized rats dopamine and dobutamine show significant calorigenic actions By subcutaneous application dobutamine is nearly as effective as noradrenaline while dopamine acts approximately five times less. Pretreatment with desipramine increases the calorigenic action of noradrenaline and accelerates its onset and its dying down simultaneously. Such a pretreatment exerts no influence whatever on the calorigenic action of dobutamine, which begins and dies down remarkably fast. Calorigenic action of dopamine is lessened by desipramine pretreatment, unambiguously. If sympathomimetics are not taken up into the neurons or their uptake is blocked by substances like desipramine, their access to the receptors is facilitated and their biotransformation possibly favoured.