. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SIGNAL TRANSDUCT1ON IN CAPITELLA BY PKC 193 Table I Effects of ion channel modulators on settlement uiii/ metamorphosis of Capitclla .s/>. / lamu Chemical % Larvae settled and metamorphosed (after I h) Potassium channel modulators KCI (20 mA/) KCI (20 mA/) + TEA ( KM) mA/) 4-Aminopyridine (100 JH III (38 vM) JH III (38 /iA/> + nigericin (500 ng/ml) Calcium channel modulators A23187 (400 nM) JH 111 (38 |) JH III (38 ijM) + NiCl, (10 mA/) JH III (38 /MA/) + ZnCI, (10 mA/) JH 111 (38 /aA/l + Verapamil (17 )
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SIGNAL TRANSDUCT1ON IN CAPITELLA BY PKC 193 Table I Effects of ion channel modulators on settlement uiii/ metamorphosis of Capitclla .s/>. / lamu Chemical % Larvae settled and metamorphosed (after I h) Potassium channel modulators KCI (20 mA/) KCI (20 mA/) + TEA ( KM) mA/) 4-Aminopyridine (100 JH III (38 vM) JH III (38 /iA/> + nigericin (500 ng/ml) Calcium channel modulators A23187 (400 nM) JH 111 (38 |) JH III (38 ijM) + NiCl, (10 mA/) JH III (38 /MA/) + ZnCI, (10 mA/) JH 111 (38 /aA/l + Verapamil (17 ) 100 5 101) 100 (I 101) 100 0 0 0 JH = juvenile hormone. 1998). Studies were therefore carried out to determine if the modulation of potassium channels may also mediate settle- ment and metamorphosis of the Capitella larvae. Increased external KCI concentrations in the seawater induced settle- ment and metamorphosis of the Capitella larvae in a con- centration-dependent manner, with an added concentration of 20 mM (30 mM total including seawater) inducing 100% settlement and metamorphosis in 1 h (Table I). These effects of KCI appear to be mediated by K+ ions and not Cl~ since addition of NaCl had no effect on settlement and metamor- phosis. The effect of tetraethylammonium chloride (TEA), a known blocker of potassium currents, was next studied to determine its effect on settlement and metamorphosis. TEA did not induce settlement and metamorphosis of the Capi- tella larvae, but instead inhibited the stimulatory response of the larvae to KCI, with a concentration of 100 mM TEA almost completely inhibiting settlement and metamorphosis (Table 11. Settlement and metamorphosis of the Capitella larvae was, however, stimulated in a concentration-depen- dent manner by 4-aminopyridine (4-AP), another potassium channel blocker. which blocks outward rectifying potassium currents. A concentration of 100 ju,jW4-AP stimulated 100% settlement and metamorphosis of the larvae within 1 h (Table
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
