Lotfi Aarab 1* , Abdejlil Daoudi 1 , Martine Imbert-Teboul 2 and Danielle Chabardès 2

1 Laboratoire des molécules bioactives (LMBSF), Unité d’immunologie et de pharmacologie, Département des sciences de la vie, Faculté des sciences et techniques. PO Box 2202, Route d’Immouzer, Fès, Maroc.
2 Laboratoire de biologie intégrée des cellules rénales, Département de biologie cellulaire, CEA Saclay, Gif-sur- Yvette, France

Abstract

The effect of dehydratation of Jerboas on the response to arginin-vasopressin (AVP), prostaglandin E2 (PGE 2 ) and the muscarinic agonist carbachol was investigated in outer medullary collecting ducts (OMCD) micro-dissected from collagenase treated Kidney. The action of these agonists was tested on the variation of the intracellular calcium concentration ([Ca 2+ ]i). On the OMCD micro-dissected from hydrated Jerboas, AVP induced an accumulation of adenosine 3’,5’-cyclic monophosphate (cAMP) and an increase of [Ca 2+ ]i. Tested in the same conditions, PGE 2 and carbachol increases the [Ca 2+ ]i in Jerboa’s OMCD. When Jerboas were dehydrated for several days, we observed that : (1) the increase of both cAMP and [Ca 2+ ]i induced by AVP was inhibited after 2 weeks of dehydratation; (2) the biphasic increase of [Ca 2+ ]i induced by PGE 2 was markedly reduced by 86.7% after 2 weeks of dehydratation; (3) the effect of carbachol on [Ca 2+ ]i was not modified by the dehydratation (only 14,3% of inhibition after 3 weeks of dehydratation). These results indicate that dehydratation of Jerboa impairs the effect of AVP and PGE2 in the renal OMCD.

Key Words : Micro-dissected ducts, cAMP accumulation, intracellular Calcium, dehydratation, desert Rodent.