Kinin effects on electrogenic ion transport in primary cultures of pig renal papillary collecting tubule cells

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Abstract
Confluent monolayers of pig renal papillary collecting tubule (RPCT) cells were formed on Millipore filters coated with collagen. They were clamped in Ussing-type chambers and used to measure short-circuit current (SCC). The monolayers had low potentials (0.1 mV) with the basolateral side positive. Small inward currents flowed under short-circuit conditions. Increases in SCC were obtained following addition of a number of agents. Receptors associated with SCC changes were disposed as follows: for kinins (e.g., lysyl-bradykinin) they were present on both sides of the tissue, while those for arginine vasopressin and norepinephrine were present on the basolateral side only. Epithelia responded to PGE2 added to the apical or basolateral face of the tissue; application to one side prevented the response from the contralateral side. The tissues also responded to forskolin, an activator of adenylate cyclase, with a sustained inward current that was sensitive to furosemide. Similar sustained inward currents were recorded following exposure to 8-bromoadenosine-3'',5''-cyclic monophosphate (BrcAMP). Responses to kinins were attenuated by inhibition of fatty acid cyclooxygenase with either indomethacin or piroxicam or by replacing chloride with impermeant ions. If the SCC was first increased with forskolin, BrcAMP, or norepinephrine, the kinin effects on SCC were either abolished or reversed. It is concluded that kinin can cause chloride secretion in RPCT monolayers, possibly via a prostaglandin or a prostaglandin-adenylate cyclase mechanism. Secondary effects of kinin, exposed by first raising tissue cAMP levels, are not precluded.