Micropuncture

KIDNEY Isolated perfused and nonfiltering kidney, 191, 31 multiple indicator dilution and the kidney kinetics, permeation, and transport in vivo, 191, 34 micropuncture techniques in renal research, 191, 72 microperfusion-double-perfused tubule in situ, 191, 98 transcapillary fluid transport in the glomerulus, 191,... 

Howell, D. S., Pita, J. C. Calcification of growth plate cartilage with special reference to studieson micropuncture fluids. Clin. Orthop. 118, 208 (1976)... 

The morphological and functional development of the kidney has extensively been studied in rats. There is a rapid differentiation of the renal cortex after birth (83). The proximal segments of the tubules grow most rapidly, and micropuncture techniques have shown that glucose is reabsorbed solely by this segment of the tubule. Baxter and Yoffey have reported that in the newborn rat the peripheral region of the renal cortex is characterized by a neogenic zone of undifferentiated tissue, which cannot store the vital dye, trypan blue. By 28 days after birth, the tubules... 

Micropuncture techniques have been applied to the direct investigation of the effect of diuretics on single nephron function. The observed changes in tubular fluid reabsorptive rates and electrolyte concentrations can be used to asses the mechanism of action. The... 

Knox FG, Marchand GR (1976) Study of renal action of diuretics by micropuncture techniques. In Martinez-Maldonado M (ed) Methods in Pharmacology, Vol 4A, Renal Pharmacology. Plenum Press, New York, London, pp 73-98... 

Several laboratories have developed methods to physically separate and characterize the metabolic capacity of glomeruli, proximal tubules, and distal tubules. These techniques can offer insight into biochemical changes associated with site-specific nephrotoxicity. Additionally, micropuncture and microperfusion experiments have been utilized to help identify specific loci of action of nephrotoxicants. 

Micropuncture Can study transepithelial transport in surface portions of proximal and distal tubules. Cannot study deep segments. 

Both classical transport systems are located exclusively in the proximal tubule of the nephron. Several techniques such as visual observations, stop-flow experiments, tubular micropuncture, in vivo and in vitro tubular microperfusions have demonstrated this particular transport capacity of the proximal tubular segment of the nephron [19]. Secretion entails an increase of proximal cell concentration of transported substrates that may become higher than in interstitium, and in some case may result in nephrotoxicity [40-42]. 

Roch-Ramel F, Roth L,ArnowJ, Weiner LM. Salicylate excretion in the rat free flow micropuncture experiments. J Pharmacol Exp Ther 1978 207 737-747. 

Infusions of AmB, intravenously or into the renal artery, induce short-term reduction in renal blood flow (RBF) and GFR, and an increase in renal vascular resistance, in both rats and dogs [83-85]. The effects of short term infusions of AmB on the renal microcirculation in rats revealed that the single nephron GFR was decreased by 2 mechanisms (Table 1) 1) a decrease in single nephron plasma flow, due to vasoconstriction of the afferent and efferent arterioles, and 2) a reduction in the glomerular capillary ultrafiltration coefficient (Kf), an effect probably mediated by mesangial cell contraction [86]. Previous micropuncture studies demonstrated a similar vasoconstriction of the afferent arteriole but also an increased permeability of the tubular epithelium to inulin [75]. Thus, the reduction in GFR after acute AmB infusions can be attributed to contraction of afferent smooth muscle cells, efferent smooth muscle cells and glomerular mesangial cells, as well as increased tubular permeability with back-leak... 

More recent studies provided evidence against a role for TGF in acute AmB nephrotoxicity. In contrast to its inhibition of TGF activity, theophylline prevented the acute renal responses to AmB by a mechanism unrelated to adenosine receptor antagonism [102]. Furthermore, micropuncture studies revealed that the AmB-induced reduction in single nephron GFR was the same irrespective of whether TGF was active or interrupted (by measuring GFR from distal and proximal tubular collections, respectively) [96]. The latter study also showed that distal tubular chloride ion concentrations were not increased by AmB, which indicated that the signal for TGF was unchanged. 

Sabra R,Takahashi K, Branch RA, BadrKF. Mechanisms of amphotericin B-induced reduction of the glomerular filtration rate a micropuncture study. J Pharmacol ExpTher 1990 253 34-7. 

Walter SJ, Laycock JF, Shirley DG. A micropuncture study of proximal tubular function after acute hydrochlorothiazide administration to Brattleboro rats with diabetes insipidus. Clin Sci 1979 57 427-434. 

Hayslett iP, Kashgarian M. A micropuncture study of the renal handling of lithium. Plugers Arch 1979 380 159-163. 

Leyssac PP, Holstein-Rathlou NH,Skott P,Alfrey AC. A micropuncture study of proximal tubulartransport of lithium during osmotic diuresis. Am J Physiol 1990 258 F1090-F1095. 

Shirley DG, Walter SJ, Sampson B. A micropuncture study of renal lithium reabsorption effects of amiloride and furosemide. Am J Physiol 1992 263 FI 128-Fl 133. 

Fransen R, Boer WH, Boer P, Koomans HA. Amiloride sensitive lithium reabsorption in rats a micropuncture study. J Pharmacol Exp Therapy 1992 263 646-650. 

Fransen R, BoerWH, Boer P, Dorhout Mees EJ, Koomans HA. Effects of furosemide or acetazolamide infusion on renal handling of lithium a micropuncture study in rats. Am J Physiol 1993 264 129-34. 

Biber TUL, Mylle M, Baines AD, et al. 1968. A study of micropuncture and microdissection of acute renal damage in rats. Am J Med 44 664-705. 

Schulz IJ. Micropuncture studies of the sweat formation in cystic fibrosis patients. J Clin Invest 1969 48 1470-7. 

Andreuccl, V.E. Manual of Renal Micropuncture, Ideleson Publishers, Naples, Italy, p. 303-7. 

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