The fall of blood pressure resulting from the stimulation of afferent nerves / by Reid Hunt.

  • Hunt, Reid, 1870-1948.
Date:
1895
Catalogue details

Licence: Public Domain Mark

Credit: The fall of blood pressure resulting from the stimulation of afferent nerves / by Reid Hunt. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    Jan. 13th. Cat; vagi cut. Stimulation of the nerve with a current a little more than just perceptible to the tongue, with the nerve at 26° C. gave a rise of 38 mm. Hg. The nerve was cooled to 10° and again stimulated with the same current; there was no effect on blood-pressure or a minute rise. The cooling was now continued to i\° C; now stimulation was fol- lowed by a fall of 20 mm.; the pressure returning at once after stimulation ceased. Water at about 26° C. was now circulated around the nerve and the stimulus again applied 110 seconds after the former one. A rise of 28 mm. followed. Similar results were obtained in an experiment upon a cat anaesthetized by division of the crura cerebri. Ether. Ether, alone or with other anaesthetics, has a marked influence in increasing the ease with which depressor effects are obtained. Very often in experiments in which this anaesthetic was used, a fall of pressure was the only result from stimulation of the sciatic at the temperature of the room. This was especially the case in experiments upon rabbits. With dogs and cats, however, if the nerve had been freshly exposed and the stimulating current was moderately strong, a rise of pressure usually occurred; in such cases cooling the nerve caused a marked fall during stimulation. If, how- ever, the current was weak or if the nerve had been exposed for some time or stimulated frequently, either a fall of pressure resulted or no change was produced, either at the temperature of the room or when the nerve was cooled. Examples of such experiments are as follows: Dec. 12th. Rabbit; vagi intact. With temperature at 23°, a weak stimulus caused a rise of 19 mm. ; the nerve was now cooled to 15° and stimulated with the same current: a fall of 9 mm. resulted. Warming the nerve in this experiment did not restore its power to produce a rise on stimulation. Dec. 13th. Dog; a.c.e. mixture. Stimulation, with a weak current, of the sciatic at the temperature of the room caused no change in the blood- pressure; with the temperature at 12°, however, the same current caused a fall of 10 mm. In this experiment weak stimulation alone did not cause a fall of pressure. Acetone Chloroform {Trichloride of Acetonic Acid'). A few experi- ments were made on cats and dogs anaesthetized with this drug; the curves of blood-pressure were remarkably uniform, and a slight rise or fall was more conspicuous and less difficult to interpret than with many 1 I am indebted for this drug to Prof. Abel, who has been using it for some time in his laboratory as an anaesthetic.