Pathophysiological significance of T-type Ca2+ channels: role of T-type Ca2+ channels in renal microcirculation

J Pharmacol Sci. 2005 Nov;99(3):221-7. doi: 10.1254/jphs.fmj05002x6.

Abstract

Since conventional Ca(2+) antagonists, with predominant blockade of L-type voltage-dependent Ca(2+) channels, elicit preferential dilation of afferent arterioles, they might ostensibly aggravate glomerular hypertension. Recently, novel Ca(2+) antagonists, with inhibitory action on L-/T-type Ca(2+) channels, have been reported to dilate both afferent and efferent arterioles. The present review attempted to characterize the renal action of these Ca(2+) antagonists and evaluated the consequences following the treatment with these agents. In contrast to conventional Ca(2+) antagonists (e.g., nifedipine), novel antagonists (e.g., benidipine, efonidipine) potently dilated afferent and efferent arterioles; their action on efferent arterioles appeared to be mediated by the T-type Ca(2+) channel blockade, probably through the inhibition of the intracellular Ca(2+) release. The comparison of the anti-proteinuric action in subtotally nephrectomized rats showed that efonidipine exerted more prominent action than nifedipine. Furthermore, Ca(2+) antagonists with T-type Ca(2+) inhibitory action inhibited renin/aldosterone release and proinflammatory process. Finally, patients with chronic renal disease given a 48-week efonidipine treatment showed reduced proteinuria, and this effect was seen even when mean arterial blood pressure failed to become less than 100 mmHg. Collectively, T-type Ca(2+) channel blockade provides beneficial action in renal injury. Various mechanisms serve to protect against renal injury, including systemic/glomerular hemodynamic action and non-hemodynamic mechanisms.

Publication types

  • Review

MeSH terms

  • Animals
  • Calcium / antagonists & inhibitors
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels, T-Type / physiology*
  • Dihydropyridines / therapeutic use
  • Humans
  • Kidney / blood supply*
  • Kidney Diseases / drug therapy
  • Microcirculation
  • Nitrophenols / therapeutic use
  • Organophosphorus Compounds / therapeutic use
  • Renal Circulation / physiology*
  • Signal Transduction

Substances

  • Calcium Channel Blockers
  • Calcium Channels, T-Type
  • Dihydropyridines
  • Nitrophenols
  • Organophosphorus Compounds
  • efonidipine
  • Calcium