Abstract
In order that the relationship between systemic circulation and renal one might be clarified, the alteration of renall blood flow by the reflectoric changes in systemic blood pressure was measured with electromagnetic flow meter. Methods: 23 dogs, weighing 8 to 15 kgs, intraperitoneally anesthetized with 35 mg/kg of nembutal sodium were divided into three groups, of which carotid occlusion was preformed in the 1st group, stimulation of the central end of cervical vagal nerve in the 2nd group, and stimluation of the central end of the sciatic nerve in the 3rd group. The one end of the cannula equipped with the electrode of electromagenetic flow meter was inserted into the left renal vein, and the other into the right jugular vein so thet the shunt could be made from renal vein to jugular vein, and the renal vein blood flow was measured by electromagnetic flow meter. The systemic blood pressure was measured with mercury manometer in the right femoral artery.The renal vascular resistance was calculated from the following equation: mean arterial pressure (mmHg)/renal blood flow in cc/min×1332×60dynes⋅sec⋅m-5 The carotid occlusion was carried out by clamping bilateral common carotid artery for 30 seconds. The electrical stimulation of the nerve was made with square waves, 30-60cycles/sec, and 5-50volts, for 15-20 seconds. Results: 1) In the carotid occlusion, slight increase in both renal vascular resistance and renal blood flow was observed accompanied with the increased systemic blood pressure. The increased renal blood flow might be considered to be caused by insufficient constriction of renal blood vessels. 2) By stimulating the central end of the cervical vagal nerve, pressor, biphasic pressor-depressor, or depressor responese occurred. In the pressor response, renal blood flow did not always show consistent changes. In the depressor response, renal blood flow always decreased. 3) In most cases of the elevation of systemic blood pressure by stimulation of the central end of the sciatic nerve, renal blood flow decreased remarkably, which showed a contraction of the renal vascular bed. Conclusion: It is suggested that renal circulation will not maintain a constant state irrespective of the changes in the systemic circulation, but will be influenced by the reflecroric alteration of the systemic blood pressure. The mode of changes in the renal blood flow can be modified by the nature of the reflex or individual difference of the animal used.
