Fig. 5.

Nucleotide hydrolysis profile in cochlear perfusate. Hydrolysis of extracellular nucleotides in artificial perilymph (AP) or divalent-cation-free artificial perilymph (DCF-AP) perfused through the cochlea and subsequently incubated with NTP/NDP/NMP substrates. a Nucleoside 5′-monophosphates AMP and UMP were not hydrolysed to their corresponding nucleosides, in contrast to GMP which was similarly dephosphorylated in both AP and DCF-AP. b Strong preference for UDP and GDP hydrolysis was divalent-cation-dependent, whilst ADP was not the substrate for the enzymes present in cochlear perfusates. c Nucleoside 5′-triphosphate hydrolysis was marginal when ATP was used as a substrate and slightly higher with UTP and GTP. This hydrolysis was not divalent-cation-dependent. Data presented as mean ± SEM (n = 5) of the HPLC peak area ratio (product/substrate), after correction for non-enzymatic hydrolysis. *P < 0.05, two-tail paired t test