Fig. 5
Sodium and proton fluxes in S. pupuratus sperm. a Speract-induced changes in fluorescence ratio (ΔR/R) indicating Na+ influx (ANG2, black) or proton efflux (pHi) (BCECF, red); signals were scaled and superimposed. Speract concentrations are shown on the right. b Mean latency ± SD (n = 7) of pHi and Na+ signal plotted vs. speract concentration. Inset: latency of pHi and Na+ signal at different speract concentrations (10 pM black circles; 100 pM white circles; and 1 nM triangles). The line represents the identity function (n = 7). c Speract-induced alkalinization monitored by pHrodo Red fluorescence in the absence (black trace) or presence (red trace) of release of cAMP from DEACM-caged cAMP with a continuously pulsing UV-LED. UV light was applied during the entire recording time. d The maximal slope of the pHrodo Red time course was plotted vs. speract concentration in the absence (black) and presence (red) of cAMP released from DEACM-caged cAMP (n = 3). e Voltage recordings during speract stimulation (1 nM) in the absence (black) or presence (red) of cAMP released from DEACM-caged cAMP
