Effects of the Antidepressants Citalopram and Venlafaxine on the Big Ramshorn Snail (Planorbarius corneus)

Abstract

Depression is a serious health issue and, being such, treatment for it has become a topic of increasing concern. Consequently, the prescription rates of antidepressants have increased by about 50% over the past decade. Among antidepressants, citalopram and venlafaxine are the most frequently prescribed in Germany. Due to the high consumption and low elimination rates of both antidepressants during wastewater purification, they are frequently found in surface waters, where they may pose a risk to the aquatic environment. For the present study, we conducted experiments with the big ramshorn snail, which we exposed to environmentally relevant and explicitly higher concentrations (1–1000 µg/L) of the antidepressants citalopram and venlafaxine. We investigated apical endpoints, such as weight, mortality, behavioural changes, B-esterase activity, Hsp70 stress protein level and superoxide dismutase activity, as well as the tissue integrity of the hepatopancreas in the exposed snails. Citalopram and venlafaxine had no effects on the B-esterase activity, Hsp70 level and superoxide dismutase activity. Citalopram exposure resulted in weight reduction and tissue reactions in the hepatopancreas of snails exposed to 1000 µg/L. In contrast, venlafaxine did not induce comparable effects, but impacted the behaviour (sole detachment) of snails exposed to 100 µg/L and 1000 µg/L of the antidepressant. These results revealed that venlafaxine can affect snails at concentrations 10 times lower than citalopram. For this, in 2020 venlafaxine was introduced in the “Surface Water Watch List”, a list of potential pollutants that should be carefully monitored in surface water by the EU Member States.

Benzodiazepine Delorazepam Induces Locomotory Hyperactivity and Alterations in Pedal Mucus Texture in the Freshwater Gastropod Planorbarius corneus

“…Locomotion in snails is greatly affected by contaminants, so much so that it is commonly used as an endpoint in toxicity testing [47][48][49][50][51]. In the case of exposure to the benzodiazepine delorazepam, we expected a depression of the motor activity [52] since GABAA-like receptors are present in mollusks [53,54], including freshwater snails (Lymnaea stagnalis, [55]).…”

Pharmaceutical pollution disrupts the behavior and predator-prey interactions of two widespread aquatic insects

“…Citalopram is used to treat depression, panic disorders, anxiety disorders, and eating disorders 43 and often shows disinhibitory effects (increased activity, increased boldness and exploration) in animals exposed to ecologically relevant concentrations (freshwater snails 44 ; three-spine stickleback 45 , 46 ; but see also Ziegler et al. 47 , 48 and Minguez et al. 49 for behavioral effects only at higher concentrations).…”

The hidden impact: exploring sublethal effects of pharmaceutical disruption on aquatic ecosystem functioning

“…Specific examples include increasing the crawling speed of marine snails, Urosalpinx cinerea and Lithopoma americanum upon exposure to venlafaxine (an antidepressant) while exposure to fluoxetine-another antidepressant decreased their crawling speed (P. P. Fong et al, 2015). In another study involving antidepressants, citalopram caused weight loss and tissue reactions in snails at a concentration of 1000 µg/L, while venlafaxine affected snail behaviour at concentrations as low as 100 µg/L, indicating that venlafaxine has a greater impact on snails at concentrations 10 times lower than citalopram (Ziegler et al, 2021).…”

“…The observed response variations between the two antidepressants emphasize the importance of considering distinct characteristics and species-specific sensitivities to pharmaceuticals within a therapeutic group. By monitoring pharmaceuticals in aquatic ecosystems solely based on their therapeutic groups we will possibly be overlooking the sub-lethal effects such as alterations in locomotion or feeding rate of one or more members of the therapeutic group (Ziegler et al, 2021). However, this is not to say that group-based monitoring approaches should be disregarded; instead, it highlights the importance of supplementing them with individual assessments to account for the nuanced effects of different pharmaceuticals in a specific therapeutic group on aquatic organisms.…”