. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ;4M 'ext IM int. IM Figure 1. Transbranchial potential differences across isolated perfused Carcinus gills bathed and perfused with 50% seawaler (including 2% ethanol) in controls and in the presence of x 10~* M indomethacin applied lo ihe external bath or the internalperfusion medium Data rep- resent means ± obtained from a sample si:e ofn = 4 gills taken from four crabs. or in the perfusate—had no significant effect on the per- fusion flow rates. In controls, unidirectional influxes of Cl (Fig. 2) great
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ;4M 'ext IM int. IM Figure 1. Transbranchial potential differences across isolated perfused Carcinus gills bathed and perfused with 50% seawaler (including 2% ethanol) in controls and in the presence of x 10~* M indomethacin applied lo ihe external bath or the internalperfusion medium Data rep- resent means ± obtained from a sample si:e ofn = 4 gills taken from four crabs. or in the perfusate—had no significant effect on the per- fusion flow rates. In controls, unidirectional influxes of Cl (Fig. 2) greatly exceeded Cl~ effluxes, a finding indicating net influx. In- domethacin had no effect on unidirectional in- or effluxes of Cr when applied at X 10~4 M in the external me- dium. Application of X 10~4 A/IM on the basolateral side resulted in a significant reduction (66%) of unidirec- tional Cl influxes. Concomitantly, influxes of Cl recov- ered quantitatively following IM removal. Unidirectional effluxes of Cl~ were not changed significantly by X 10~4 M internal IM. The lowest IM concentration that signif- icantly inhibited unidirectional Cl~ influxes was 10 4 A/ which reduced Cl~ influx rates by 12%; complete inhi- bition was observed at 10~3 M. Comparable effects of IM were obtained on fluxes of Na+ (data not shown). It was reported earlier that depolarization of isolated perfused shore crab gills accompanies inhibition of uni- directional ion influxes (14). Accordingly, we demonstrate here depolarization of the epithelium and inhibition of transgill net influx of Cl~ (Fig. 2) and Na+ by IM. The effects on PDs and ion fluxes were only observed when IM was applied in the internal perfusate. Thus, we assume that the IM-sensitive transport step is located at the ba- solateral side of the epithelial cell. The rapid and quantitative reversibility of depolariza- tion and inhibition of Cr-influx upon IM removal indi- cates that the drug is not irreversibly bound in th
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
