Abstract
Several attempts have been made to find a nervous mechanism for the release of histamine from body tissues, 1 , 2 but thus tar the only evidence that such may exist has been indirect. 3 The present study deals with the release of histamine by the skin upon stimulation of sympathetic nerves. The epidermal layer of the skin contains relatively large quantities of histamine (24 γ/g).
Experiments were carried out on rabbits, unanesthetized or anesthetized lightly with urethane or ether. The cervical sympathetic trunk and its superior ganglion were prepared for stimulation with bipolar electrodes (4 to 60 sec, primary 3 volts, secondary coil at 10 cm). Blood samples obtained from the great auricular vein by venipuncture before and after nerve stimulation were compared for their ability to contract an isolated segment of guinea pig ileum according to the method of Schultz and Dale. Atropinized Ringer-Locke solution was used in the muscle bath in every case. Standard histamine solutions were used for comparison of contractions.
In early experiments the blood samples were allowed to clot; the serum obtained was diluted immediately with Ringer's solution or buffer solution of pH 7.15 and tested on the guinea pig ileum. In these experiments (10 animals) serum obtained 15 to 60 seconds following nerve stimulation almost invariably produced a greater contraction of the guinea pig ileum than the control serum (15 to 50% greater). This difference was present after and often increased by heating the diluted sera in a water bath at 60° to 70°C for 30 minutes, provided the pH of the sera was not above 7.15. The entire contractor effect of both control and stimulation sera could be abolished by previous addition of 0.5 γ of thymoxyethyldiethyl-amine to the muscle bath.
Get full access to this article
View all access options for this article.