title: The activity of isolated snail neurons controlling locomotion is affected by glucose.
abstract: The involvement of serotonin in mediating hunger-related changes in behavioral state has been described in many invertebrates. However, the mechanisms by which hunger signals to serotonergic cells remain unknown. We tested the hypothesis that serotonergic neurons can directly sense the concentration of glucose, a metabolic indicator of nutritional state. In the snail Lymnaea stagnalis, we demonstrate that completely isolated pedal serotonergic neurons that control locomotion changed their biophysical characteristics in response to glucose application by lowering membrane potential and decreasing the firing rate. Additionally, the excitatory response of the isolated serotonergic neurons to the neuroactive microenvironment of the pedal ganglia was significantly lowered by glucose application. Because hunger has been reported to increase the activity of select neurons and their responses to the pedal ganglia microenvironment, these responses to glucose are in accordance with the hypothesis that direct glucose signaling is involved in the mediation of the hunger-related behavioral state.
authors: Laboratory of Comparative Physiology, Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia.
authors: Varvara
authors: V
authors: Dyakonova
authors: Balaton Limnological Institute, MTA Centre for Ecological Research, Tihany, Hungary.
authors: László
authors: L
authors: Hernádi
authors: Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Shido, Sanuki 769-2193, Japan.
authors: Etsuro
authors: E
authors: Ito
authors: Laboratory of Comparative Physiology, Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia.
authors: Taisia
authors: T
authors: Dyakonova
authors: Laboratory of Comparative Physiology, Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia.
authors: Igor
authors: I
authors: Zakharov
authors: Laboratory of Comparative Physiology, Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia.
authors: Dmitri
authors: D
authors: Sakharov
keywords: Lymnaea stagnalis; behavioral state; extrasynaptic release; serotonergic neuron; volume transmission