Table 2.

Nucleotide release channels in the renal epithelium

Channel	Tubule Segment	Localization	Comments	Reference Nos.
Cx30	Rat: mTAL, cTAL, DCT, CD; mouse, rabbit: β-IC of CNT and CD	Apical	Good functional evidence, KO control	331, 340, 478, 496
Cx37	Rat, mouse: TAL, DCT; less in PT, CD	Basolateral	No functional evidence, localized to basolateral infoldings and interdigitations	488
Panx1	Mouse: PT, tDL, CD	Apical	Lower urinary ATP in Panx1 KO mice	188, 237
LRRC8A	Rat: Henle’s loop, IMCD	Only mRNA	Function only in Xenopus oocytes	160, 298
Maxi anion channel	Mouse, rabbit: MD	Basolateral	Suggested plasma membrane variant of mitochondrial VDAC	32, 371

PT, proximal tubule; tDL, thin descending limb; mTAL, medullary thick ascending limb; cTAL, cortical thick ascending limb; MD, macula densa; DCT, distal convoluted tubule; CNT, connecting tubule; CD, collecting duct; IMCD, inner medullary collecting duct; β-IC, β-intercalated cell; KO, knockout; VDAC, voltage-dependent anion channel. [Note from other organs: the CALHM channels were clearly identified as ATP release channels necessary for transduction of taste perception (503).]