Probenecid

Probenecid is able to prevent the efflux of calcium-sensitive fluorescent dyes during studies of cellular calcium mobilization. Probenecid (2.5 mM) is found to block the export of Fura-2 from 1321N1 astrocytoma cells, and does not change the basal calcium concentration or the muscarinic calcium response. ^[1] Probenecid is a potent transient receptor potential vanilloid 2 (TRPV2) agonist. Probenecid selectively induces increase in intracellular Ca²⁺ influx in HEK293T cells transiently expressing exogenous TRPV2. ^[2] Probenecid is able to interact with organic anion transporters (OAT). 0.1 mM Probenecid efficiently inhibits ATP-dependent active vesicular N-ethylmaleimide glutathione (NEM-GS) uptake by Human Multidrug Resistance Proteins 1 (MRP1) and MRP2. In isolated Sf9 cell membranes, Probenecid stimulates ATPase activity of MRP2 with approximate KACT of 250 μM, but inhibits ATPase activity of MRP1. ^[3] Probenecid is an inhibitor of the hTAS2R16, hTAS2R38, and hTAS2R43 bitter taste receptors. 1 mM Probenecid attenuates saccharin-induced calcium flux responses of hTAS2R16 to near baseline levels. Probenecid dose-dependently inhibits hTAS2R16 (in the presence of 3 mM salicin) and hTAS2R38 (in the presence of 300 μM PTC). This activity is independent of Probenecid's activity as a transport inhibitor, but is concerning with Probenecid interaction with the receptor. ^[4]

Probenecid is an inhibitor of organic transport in vivo. Probenecid is able to decrease the renal clearance of antibiotic, such as penicillin, which enhances serum levels of antibiotic. Probenecid enhances the renal excretion of urate by acting as a competitive inhibitor of OAT, which prevents OAT-mediated reuptake of uric acid from the urine to the serum. Probenecid is found to block acid metabolites from exiting the central nervous system, and is a competitive inhibitor of monoamine transport in the kidney, liver, and the eye. ^[5]