Arteries

From ordinary amounts there is regularly no change in arterial pressure, but when intoxicating doses are given, there is a slow and very gradual moderate fall. The arterioles are dilated, as shown by the increase in volume of an organ placed in an oncometer. This is due to depression of the vasoconstrictor center, for in an animal with spinal cord severed to cut off central control of the splanchnic arteries the pressure tends to rise. In perfusion of an isolated viscus there is no effect on the arteries unless the alcohol percentage is above that compatible with life.

Brooks, experimenting with unanesthetized animals, found that, about fifteen minutes after alcohol was placed in the stomach through a gastric fistula, there resulted a very gradual fall in pressure that lasted about an hour. When the alcohol was given intravenously in small amounts, there was either no change in pressure, or a slight fall, followed by rapid recovery; from large amounts there was a continuous and gradual fall, with decreased amplitude of the pulse and increased rate.

Though, ordinarily, there is no rise in arterial pressure, the rate of flow, as measured by the stromuhr, is increased (Wood and Hoyt). This means a greater supply of blood to the organs, an effect not appreciated from blood-pressure experiments.

The cutaneous arterioles are regularly dilated, even from therapeutic doses, so that the skin is flushed, and there is a feeling of warmth and comfort and a tendency to sweating. In susceptible persons even a teaspoonful of a strongly alcoholic tincture is enough to flush the face or even to give a feeling of light-headedness.

Summary of Effects upon the Circulation:

1. Before Absorption

Reflex stimulation and rise in arterial pressure from local irritation of the mouth or throat. This is the main action upon the circulation.

2. After Absorption

(a) From moderate amounts, slight direct stimulation (Langendorff, Loeb, Wood and Hoyt), slight depression (Lieb) of the heart muscle, and dilatation of the skin vessels; from large amounts, direct depression of the heart muscle. (b) Depression of vasoconstrictor and vagus centers. (c) Acceleration of blood-flow without rise in blood-pressure, (d) Dilatation of the skin vessels, (e) In debility it may serve as a source of energy for the heart.

Respiration

Willmann gave a rabbit a little oil of mustard in 10 c.c. of saline by mouth. There was no effect on respiration, though the stomach mucosa was very red and irritated. He gave a rabbit alcohol, and though the stomach did not show any irritation and did not differ from that of a control, there was great increase in the depth and frequency of respiration. He believed, therefore, that the stimulus was not from irritation of the stomach.

Experiments were also made on human beings by Binz and his pupils. In one case, for example, 2 1/2 ounces (75 c.c.) of old sherry was given at 8.25 A. m. The respiration rose from 3 to 4.25 liters of air per minute, reached 5 liters at 10.30, then fell again, but was 4 liters at 11.30. The student was somnolent during this time, as he was unaccustomed to wine.

To test the effect on respiration in fatigue, a boy of fifteen years, weighing 45 kilos, was given 20 c.c. alcohol plus 12 gm. sugar, a little lemon-juice, and 80 c.c. water. How much effect the sugar would have was not determined. The effects were as follows:

(a) When not fatigued -

in 10

minutes after alcohol - air resp. =

+

6.39

per cent.

40

" " " " " =

+

2.74

"

60

" " " " " =

-

7.77

"

(b) When slightly tired -

in 10

" " " " " =

+

12.00

"

30

" " " " " =

+

11.20

"

40

" " " " " =

+

4.25

"

(c) When very tired -

in 10

" " " " " =

+

26.80

"

30

" " " " " =

+

33.19

"

40

" " " " " =

+

52.34

"

Weissenfeld tested 74 cases, and Wendelstadt, 55. These men, and Zuntz and Bardez, von Jaksch, and Geppert obtained uniformly similar results. Allen and Dubois found that "the ingestion of alcohol in diabetes was sometimes followed by respiratory quotients higher than would be theoretically expected."

Therefore alcohol during fasting or fatigue causes a considerable increase in respiration, the same increase occurring during sleep. "The increase is apparently central, and is greatest from wines because of their ethers" (Binz).

Loewy's experiments seem to show that there is no increase in the sensitiveness of the center to carbon dioxide, and the exact site of action of alcohol in increasing respiration is not known. In late stages of poisoning the respiratory center becomes greatly depressed.

Temperature

Through the dilatation of the skin vessels and the sweating, alcohol increases the dissipation of heat, and so tends to lower the temperature. As the skin is the seat of the important temperature nerve-endings, the great amount of blood in the skin vessels gives a feeling of warmth. It also makes one more susceptible to changes in the surrounding temperature, so that though on a cold day a drink of whisky may make one feel warm, it is a spurious warmth; for the dilatation of the skin vessels which makes the feeling of warmness results in more blood being brought to the surface to be cooled, so that the body temperature falls. In other words, there is excessive heat dissipation. In arctic explorations the men are never allowed liquor at all, because it makes them more susceptible to cold. Whisky is often effectively employed to prevent a cold after exposure, on the theory that dilatation of the cutaneous arterioles will counteract the results of chilling of the surface. In very hot, humid weather alcohol predisposes to heat-stroke, but this is probably due to its effect on the central nervous system.

Heat production shows an increase during the stage of intoxication owing to the increased activity, and a decrease during the stage of stupor, owing to depression of activity. Alcohol in medicinal amounts is regularly a mild antipyretic.

It might be thought that the oxidation of alcohol would result in excessive heat production, but, as we have learned, alcohol, in being oxidized, does not increase the normal oxidation, but merely replaces a part of the normal oxidizable material, i. e., food.