Probenecid relaxes pig bladder muscle and boosts cyclic nucleotide relaxants
- Probenecid, known to block organic acid transporters, MRPs and pannexin-1, was tested on isolated pig detrusor muscle.
- It relaxed the tissue in a concentration-dependent but partial manner, and enhanced relaxation by cAMP- and cGMP-raising agents including a PDE5 inhibitor.
- The enhancement depended on the soluble guanylyl cyclase pathway, with higher intracellular and lower extracellular cGMP.
- Selective OAT, P2X7 and pannexin-1 tools did not reproduce the effect; PDE3A, PDE5 and MRP4 were found in bladder tissue.
💡 Points Based on the abstract
Probenecid is a dirty tool: it hits OAT, MRPs and pannexin-1, and the selective probes failed to copy the effect, so the mechanism is unassigned. MRP4 efflux blockade is the obvious suspect, which a clean MRP4 inhibitor or knockdown would test. Also unresolved: whether human detrusor and tolerable free exposure reproduce this.