ЭЛЕКТРИЧЕСКАЯ АКТИВНОСТЬ ИДЕНТИФИЦИРОВАННЫХ НЕЙРОНОВ ЦНС МОЛЛЮСКА LYMNAEA STAGNALIS В УСЛОВИЯХ ОСТРОЙ ГИПЕРГЛИКЕМИИ

Abstract

Rapid responses of the key interneurons identified in the respiratory (RPeD1), locomotor (LPeD1) and cardioregulatory (VD1/RPaD2) networks of the CNS ganglia in a mollusk Lymnaea stagnalis under the action of D-glucose (1 and 10 mM) were studied. In acute hyperglycemia (10 mM), an increase in the firing frequency of VD1/RPaD2 neurons and its decrease in LPeD1 neurons, as observed already within the first minute after exposure, were detected; at the same time, the firing frequency of RPeD1 neurons remained intact. Bath application of glucose at lower concentrations (1 mM) led to no significant changes in the electrical activity of all the above neurons. The observed effects were not associated with an increased production of reactive oxygen species (ROS) in the cytoplasm, since the fluorescent probe (2′,7′-dichlorodihydrofluorescein diacetate) failed to reveal their accumulation in the cell suspension of CNS ganglia after glucose (10 mM) application during the short-term period (5 min) as compared to the control. Action potential shape analysis under conditions of hyperglycemia (glucose, 10 mM) revealed in highly glucose-sensitive VD1/RPaD2 neurons an increase in the rate of slow membrane depolarization to reach a threshold potential, while the other spike phases remained unchanged. It is assumed that the glucose effects toward the frequency characteristics of the above L. stagnalis interneurons are realized via modification (intensification) of the electrogenic Na+-coupled glucose transporter and depend on their functional affiliation (incorporation into a specific neural network).