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After a month of measuring the blood pressure of rabbits was operated on the second time.
Animals of the first series we have generirovanie carotid sinus, but not so as it was done in the laboratory of Goering, and maintaining a common, external and internal carotid artery intact: deleted carotid the glomeruli, crossed the nerves of Goering, removed his outer shell with all three of the arteries in the area of branching, and then smeared the blood vessels that are exempt from the outer shell, a strong solution of carbolic acid to destroy the remaining nerves, if they survived. Nerves of Zion also cut. All this was done on both sides, and then the wound was sutured. Operation is simple, lightweight, rabbits suffer great it under local anesthesia and even during the operation have not given up the carrots. In the morning it is already possible to record blood pressure, which, however, does not change within two weeks. Why is entirely unclear. Then developing hypertension. The heart is not changed, and mean arterial pressure has risen due to the increase of vascular tone, not because of the increased performance of the heart, as some thought before. All people with hypertension.
Reflexes blood pressure for clamping of the common carotid arteries decreased, but did not disappear. This is understandable, because in the internal carotid artery over a large area, there are also mechanoreceptors fields - not only in the carotid sinus. During the two-year observation hypertension in these rabbits have not decreased.
The experiences of the second series were much more complicated: transection warm branches of the left vagus nerve, that is, partial denervation of the heart. We already know That the heart nerves are mainly centripetal information (95 %) and only slightly commands "from above" (5 %).
The operation, of course, is connected with the opening of the chest cavity, there is a pneumothorax (air penetration into the pleural cavity). Natural breathing is impossible, the operation is under artificial respiration. The device rhythmically blows air into the trachea.
Despite the rather traumatic surgery, the rabbits recovered quickly, and complications none were. Blood pressure in them after surgery slightly, but quickly increased, and the pulse rate fell (where the notorious vagusnye constant braking?). The increase pressure was slightly less than in the first series of experiments, can therefore be assumed that the centripetal impulses to heart twigs left vagus nerve less intense than in both nerves Ziona and both nerves Goring. The reader, I hope it is clear that the decrease of the heart rate and increased blood pressure in experiments both series crosses the prevailing today's point of view on the "antagonistic" the role of the vagus nerve and simpaticos, the matter is much more complicated.
But we strive for the most complete shutdown sensitive (parasympathetic) nerves of the heart; we are hampered by the fact that the branches of heart vagonov - mixed, i.e. carry impulses in both directions. So you have to turn off and centrifugal and centripetal alarm: to vasomotor centers and, on the contrary, to the heart. Operation is fully denervated heart does not stop, it was known Ludwig, but it is important for us to know how does the impulses of receptors of the heart, addressed to the centres, On the vessels of the periphery, to see the response of the sympathetic nerves in the transection vagusnye branches of the heart.

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