Male preputium eversion in Biomphalaria straminea caused by fluoxetine

Lam Hoi-ka, Edwin ten Winkel, bbPharma

Fluvoxamine (=Fluvox®), a selective serotonin reuptake inhibitor (SSRI) was tested for its ability to induce preputium eversion in Biomphalaria straminea in order to clarify the physiological mechanism of eversion. Biomphalaria straminea is a snail species that was accidentally introduced to Asia in recent years। Methioheptin and serotonin were added as controls. Fluvoxamine was found to have an MED of 10-50μM (p<0.0001). The receptor antagonist methiothepin was found to have an MED of 1 -10 μM (p <0.0001). Serotonin did not induce eversion and did not block methiothepin-induced eversion. This suggests that fluvoxamine is not acting as SSRI, but possibly as a receptor ligand.

Reference
Yapp, J.: Distribution of the Schistosome Vector Snail Biompholaria straminea: J. Mollus. Stud. 1990; 56: 47-55

Male preputium eversion in Biomphalaria alexandrina caused by SSRI's

Lam Hoi-ka, Edwin ten Winkel, bbPharma
Abstract. Eversion of the male preputium is an initial step in the copulatory behavior of several species of freshwater snails. Serotonergic mechanisms are involved in eversion in Biomphalaria glabrata snails as methiothepin, a serotonin receptor antagonist, has been shown to cause long-lasting dose-dependent eversion.
A number of selective serotonin reuptake inhibitors (SSRI's) were tested for their ability to induce preputium eversion in B. alexandrina in order to clarify the physiological mechanism of eversion. Methioheptin and serotonin were added as controls. Results were as follows: (SSRI's) fluoxetine (=Prozac®, 10–100 μM; p<0.0001), fluvoxamine (=Fluvox®, 10-50μM; p<0.0001), paroxetine (=Seroxat®, 10-50μM; p<0.0001). The receptor antagonist methiothepin (1 -10 μM; <0.0001). Serotonin did not induce eversion and did not block methiothepin-induced eversion. This suggests that the SSRI's are not acting as SSRI, but possibly as a receptor ligand.