PMID: 7514597May 13, 1994Paper

Differential activation of cation channels and non-selective pores by macrophage P2z purinergic receptors expressed in Xenopus oocytes.

The Journal of Biological Chemistry
L C Nuttle, G R Dubyak

Abstract

In macrophages and certain other cell types, extracellular ATP4- can increase plasma membrane permeability through activation of the P2z purinergic receptor. This permeability change involves the induction of non-selective pores which are permeable to molecules with M(r) < or = 900. Electrophysiological studies indicate that agonist occupation of P2z purinergic receptors can additionally activate cation channels which may be distinct from the non-selective pores. We have observed that mammalian P2z purinergic receptors can be expressed in Xenopus oocytes injected with mRNA from the BAC1.2F5 murine macrophage cell line. Under voltage-clamp analysis, these oocytes exhibit a multiphasic inward current in response to ATP or 3'-O-(4-benzoyl)-benzoyl-ATP (BzATP), a selective agonist for the P2z purinergic receptor. This ATP/BzATP-induced current is characterized by a rapidly activated phase which is followed by a delayed, but steady, increase in conductance. We have used two-electrode voltage-clamp analysis and ion substitution to further characterize these P2z purinergic receptor-induced currents as expressed in mRNA-injected oocytes. N,N-Hexamethylene amiloride (HMA), a potent inhibitor of various exchangers and channels, selective...Continue Reading

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