Purinergic P2 receptors modulate colonic ion transport. Activation of luminal P2Y4 receptor stimulates K⁺- and Clsecretion, whereas luminal P2Y2 receptor stimulates K⁺ secretion and inhibits Na⁺ absorption. The source of extracellular nucleotides in intestinal epithelial physiology remains obscure. Evidence from other tissues suggests mechanically stimulated, non-lytic cellular nucleotide release. This issue was investigated in an Ussing chamber using mouse distal colon and comparing electrogenic Na⁺ transport induced after low Na⁺ diet in P2Y2 WT and KO mice. In one series distal colon was mounted without removing the muscular layers. The time course and magnitude of Na⁺ transport was similar in both genotypes (Isc(20min): ­725±158 [n=6, WT] vs. ­719±109 mA/cm ² [n=13, KO]). In the second series only the mucosal sheet was mounted after gently removing the muscular layers. This removal caused a major reduction of Na⁺ transport in WT mouse colon (Isc(20min):­213±57 [n=10, WT] vs. ­460±99 mA/cm ² [n=10, KO]). These results indicate that a mechanical perturbation of the freshly isolated tissue reduces Na⁺ absorption, likely via the activation of a luminal P2Y2 receptor. We suggest that mechanical stimulation has caused nucleotide release, resulting in inhibition of Na⁺ transport. We assume that mechanical stimulation of colonic epithelia during stool passage favours P2 receptor-dependent ion and water movement into the lumen supporting the faecal passage.