Larval settlement and metamorphosis of the invasive biofouler, Mytilopsis sallei , in response to ions and neuroactive compounds.

In this study, we investigated larval settlement and metamorphosis of the invasive foulerMytilopsis salleiexposed to ions, neurotransmitters and blockers inhibiting their respective actions. Excess K+effectively induced larval settlement and metamorphosis, while the voltage-gated potassium channel blocker, TEA, significantly inhibited the K+inducing effect, suggesting that a voltage-gated potassium channel may play a role inM. salleisettlement and metamorphosis. Excess Ca2+did not induce larval settlement and metamorphosis, while Mg2+andinhibited both. Among the neurotransmitters, GABA did not induceM. salleilarvae to settle and metamorphose at 10−6–10−4 M concentrations, while 5 × 10−5–10−4 Ml-DOPA (a dopamine precursor), 5 × 10−6–10−4 M dopamine (an epinephrine precursor) and 5 × 10−5–10−4 M epinephrine significantly induced larval settlement and metamorphosis, indicating the presence of an epinephrine biosynthesis pathway in this species and its role in the regulation of larval settlement and metamorphosis. Furthermore, the inducing effect of dopamine onM. salleisettlement and metamorphosis was inhibited by SCH23390, a selective D1 dopamine receptor antagonist. Similarly, the inducing effect of epinephrine was inhibited by chlorpromazine, anα1-adrenergic antagonist, suggesting that the D1 dopamine receptor andα1-adrenoceptor may play active roles in the processes of settlement and metamorphosis ofM. salleilarvae. Here, we have shown for the first time the responses of larval settlement and metamorphosis of dreissenid mussels to pharmacologically active compounds. The results provide new insights into the biochemical mechanisms underlying larval settlement and metamorphosis ofM. sallei, which may be useful to develop effective strategies to control this invasive fouling organism. [ABSTRACT FROM PUBLISHER]