RESPONSE OF TISSUES TO SYMPATHETIC STIMULATION

¹ Department of Pharmacology, University of Edinburgh

1. The effects of nerve stimulation and of adrenaline administration have been studied on the auricle of the frog and the nictitating membrane, gut, and blood-pressure of the cat.

2. The summation effects observed with stimulation at varying frequencies can be explained on the assumptions that a mediator is liberated, that it is destroyed in the tissues and that the course of destruction approximates to that of a monomolecular reaction.

3. The shortest time for half-destruction calculated is 5 secs.

4. The durations of the responses to nerve stimulation indicates longer times for half-destruction than those calculated from the sum-mation of stimuli at varying frequencies. Lag in the response of the tissue is likely to affect duration more than summation, and hence the times calculated from summation experiments are regarded as the more probable.

The expenses of this research were defrayed by a grant from the Moray Fund of the University of Edinburgh, and one of the authors (J. R.) is in receipt of a grant from Messrs. Imperial Chemical Industries Ltd. We desire to express our thanks for this help.