Function of smooth muscle of the rat renal pelvis—response of the isolated pelvis muscle to angiotensin and some other substances

Abstract

Summary The circular component of the renal pelvis muscle of the rat appears as an intact band around the tip of the papilla. The isolated pelvis muscle strip showed spontaneous rhythmic contractions in Locke solution at 38° C. The rate of contractions corresponded with the rate of pressure fluctuations recorded during free‐flow from a ureteral catheter inserted up to the renal hilum of anaesthetized rats. Angiotensin and adrenaline (13 ng/ml) produced a rise in tone of the isolated pelvis muscle, and an increase in the rate of spontaneous contractions; noradrenaline produced mainly an increase in the amplitude and rate of spontaneous contractions. Angiotensin and noradrenaline injected intravenously also produced an increased rate of pressure fluctuations recorded from the ureteral catheter. Acetylcholine, nicotine and 5‐hydroxytryptamine had no effect on the isolated tissue, but isoprenaline was capable of causing a decrease, and tyramine an increase, in the rate of spontaneous contractions in high dose (0.33 μg/ml). An increase in the tone of the circular pelvis muscle could lead to a reversible obstruction of urine outflow from the kidney.

Angiotensin II Promotes Development of the Renal Microcirculation through AT1 Receptors

“…9,35 We observed no changes in VEGF mRNA level, VEGF immunolocalization, and vascular bundle organization in two experimental rat models with postnatal polyuria and intact AngII signaling. The microvascular injury is therefore not caused by excessive urine …”

Relationship between pelviureteral peristaltic frequency and urine flow change evoked by autonomic drug administration.

“…It was reported by Butcer et al (1957) and Finberg and Peart (1970) that acetylcholine had little or no effect on the calyceopyeloureter system. Gruber (1928) and Deane (1967) noted enhancement of ureteral peristalsis by acetylcholine, whereas Chen et al (1957) and Borgstedt et al (1962) described that acetylcholine suppressed peristaltic movement of the ureter.…”

Effects of Field Stimulation on Cholinergic Fibers of the Pelvic Region in the Isolated Guinea Pig Ureter

“…FINBERG and PEART(1970),in the experiments recording the contraction of circular muscle in the isolated pelvis,found that acetylcholine was without effect,suggesting that the acetylcholine receptor does not exist in the circular muscle of the pelvis.The fact indicates that acetylcholine receptors may exist in the longitudinal muscles,because the preparations consisting of longitudinal and circular muscles used in the present experiments respond to acetylcholine evidently.A marked decline of the sensitivity to acetylcholine by removal of the pelvic region is compatible with the fact that there is relatively rich innervation on a specific region of smooth muscles in the pelvic region (DIXON and GOSLING,1971). ELBADAWI and SCHENK(1969)and DUARTE-ESCALANTE et al(1969)showed the existence of cholinergic and adrenergic nerves along the entire length of the ureter.The latter group also pointed out that a type of concentrated neuron-like or ganglion cell has been found at the lower part of the renal pelvis and that the cholinergic innervation is better developed than the adrenergic one at the ureteropelvic junction.These facts consist with the present results that the pelvic region is different from the other part of the ureter in sensitivity to acetylcholine and that,in spite of the existence of cholinergic nerves in the upper ureter,receptors reacting to acetylcholine are extremely few as compared to the pelvic region.Accordingly,the observations in the Magnus method are consistent with findings in the intact dog by KIIL and KJEKSHUS(1966)and pelvic region,as well as the higher cholinesterase activity in the calyx-pelvis.…”