Mechanisms of transport of Na+ and Cl− in the lizard colon

doi:10.1016/0300-9629(87)90009-0

Comparative Biochemistry and Physiology Part A: Physiology

Volume 87, Issue 4, 1987, Pages 883-887

Comparative Biochemi...

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Abstract

1.
1. Ionic fluxes of sodium and chloride across lizard colon mucosa were measured and compared with the electrical characteristics of the tissue under voltage-clamped conditions.
2.
2. In a Ringer-bicarbonate solution there was both a net sodium flux (J_net^Na) and a net chloride flux (J_net^cl) from mucosa to serosa. The net flux residual (J^R) was near zero, indicating that net sodium and chloride transport is the result of an electrically neutral transport mechanism.
3.
3. In the presence of sodium, the net chloride flux was abolished and the short-circuit current (I_sc) and the electrical potential difference (PD) were unchanged. In the absence of chloride the net sodium flux was abolished and the short-circuit current and electrical potential difference were not modified.
4.
4. From an analysis of the effects of the inhibitors, furosemide, amiloride and disulfonic stilbene (DIDS), a plausible model was developed to explain the characteristics of sodium and chloride absorption.

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Cited by (14)

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2019, Mader's Reptile and Amphibian Medicine and Surgery
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Regulation of amiloride-sensitive Na<sup>+</sup> absorption in the lizard (gallotia galloti) colon by aldosterone
1991, Comparative Biochemistry and Physiology -- Part A: Physiology
- 1.
  1. Acute (AT) or chronic (CT) administration of exogenous aldosterone brought about a considerable increase in transmural potential difference (PD), short-circuit current (Isc) and net sodium flux (J_net^Na).
- 2.
  2. A good relationship between Isc and J_m-s^Na was observed in CT but not in AT or UC (untreated controls).
- 3.
  3. Addition of mucosal amiloride reduced Isc in AT and CT colons, but did not cause any change in UC colons. The relationship between Isc and J_m-s^Na, observed in CT was totally suppressed by the diuretic.
- 4.
  4. J_net^Na was reduced in AT tissues and abolished in CT colons by amiloride.
- 5.
  5. The present results strongly suggest that aldosterone levels quantitatively and qualitatively modify sodium absorption across colonie mucosa in a dose-dependent fashion and that lower levels of the hormone are required to induce the electrogenic Na absorption than to suppress the electroneutral transport.
Modulation of active potassium transport by aldosterone
1990, Comparative Biochemistry and Physiology -- Part A: Physiology
- 1.
  1. The role of aldosterone on active potassium transport across lizard colon under voltage-clamped conditions has been investigated.
- 2.
  2. Control colons exhibited no net potassium flux (J^k_net) despite of the existence of active opposite unidi ectional fluxes.
- 3.
  3. An important net secretory potassium flux was found in short-circuited aldosterone-stimulated colons.
- 4.
  4. Mucosal amiloride did not change (J^k_net) either in control or aldosterone-stimulated colons.
- 5.
  5. Luminal barium alters K ⁺ transport in a manner consistent with the presence of barium-sensitive conductances at the apical membrane of both control and aldosterone-treated colons.
- 6.
  6. The effects of ouabain and barium on control and aldosterone-induced potassium flows were consistent with a model involving basolateral uptake by an Na ⁺-K ⁺-ATPase and conductive exit across the apical membrane.
- 7.
  7. The stimulatory effect of aldosterone on potassium secretion is associated with parallel increases of both basolateral K ⁺ entry and the apical conductive pathway.

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Comparative Biochemistry and Physiology Part A: Physiology

Abstract

References (29)

Electrical potential difference across cloaca and colon of the Australian lizards Amphibolorus omatus and A. inermis

Comp. Biochem. Physiol.

Mechanism of transport of Na, Cl and K in the human colon

Gastroenterology

Colonic absorption of inorganic ions and volatile fatty acids in the rabbit

Comp. Biochem. Physiol.

Na⁺ channels and amiloride-induced noise in the mammalian colon

Biochim. biophys. Acta

Osmoregulation

Effect of conjugated dihidroxi bile salts on electrolyte transport in rat colon

J. clin. Invest.

Furosemide inhibition of chloride transport in human red blood cells

J. gen. Physiol.

Influence of vasopressin and calcium on electrolyte transport across isolated colonic mucosa of the rat

J. Physiol.

The nature of the membrane sites controlling anion permeability of human red blood cells as determined by studies with disulfonic stilbene derivates

J. Memb. Biol.

Effects of spironolactone and amiloride on corticosteroid-induced changes in colonic function

Am. J. Physiol.

Post-natal development of the amiloride sensitive sodium transport in pig distal colon

J. Physiol., Lond.

Inhibition of active chloride absorption in rabbit colon by DIDS (Abstract)

Electrogenic chloride secretion by mammalian colon

Ion transport by rabbit colon. I. Active and passive components

J. Memb. Biol.

Cited by (14)

Urology

Cardiology

Renal Disease in Reptiles: Diagnosis and Clinical Management

Renal Disease in Reptiles: Diagnosis and Clinical Management

Regulation of amiloride-sensitive Na<sup>+</sup> absorption in the lizard (gallotia galloti) colon by aldosterone

Modulation of active potassium transport by aldosterone