Data from: Electrochemical sensing of hormonal serotonin levels in Crayfish

The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) has been
implicated as a key biomarker that regulates a range of neurobehavioral
functions. 5-HT also plays a prominent role in modulating social behavior
across species. Here, we report the successful differentiation of hormonal
(circulatory) 5-HT concentrations in socially isolated and communal
crayfish samples by a surface-modified carbon fiber microelectrode
electrochemical sensor. Monitoring 5-HT concentrations across social
conditions provided important insights into mechanisms linking isolation
to neurohormones that guide behavior. Utilizing surface coatings and
electrochemical etching, our sensor can detect endogenous, nanomolar
concentrations of 5-HT in vitro from crayfish hemolymph (i.e., blood)
collected from communally housed animals and those isolated for one or
seven days. Our measurements revealed that crayfish responses to isolation
varied by species: Procambarus crayfish isolated for seven days exhibited
a major increase in 5-HT compared to communally housed or short-term
isolated conspecifics, whereas for Faxonius crayfish, the hormonal
concentrations of 5-HT peaked after one day of isolation but paralleled
the levels of communally housed crayfish after one week of isolation.
These findings underscore the complex nature of neurochemical pathways in
response to social conditions, demonstrate the sensor's utility for
studying 5-HT dynamics, and provide a method for monitoring temporal
changes in hormonal 5-HT following social isolation.