Respiratory reactions to stimulation and blockade of GABAA receptors of the retrotrapezoid nucleus in rats
DOI:
https://doi.org/10.33910/2687-1270-2021-2-4-471-475Keywords:
retrotrapezoid nucleus, GABAA receptors, muscimol, bicuculline, external breathingAbstract
The respiratory reactions to microinjections of muscimol and bicuculline solutions into the retrotrapezoid nucleus (RTN) were studied in acute experiments on anesthetized rats breathing ordinary atmospheric air. It was found that the activation of GABAA-receptors of the RTN by muscimol has inhibitory effect on external respiration, reducing its minute volume and volumetric rate of inspiratory flow due to prolongation of inspiration and expiration and a decrease in the tidal volume. The reactions to microinjections of the GABAA-receptors antagonist bicuculline into the RTN were not unambiguous, but in most cases they manifested as an increase in minute lung ventilation with an increase in tidal volume and volumetric inspiration rate. The data obtained indicate that GABAA-receptors are involved in the activity of the RTN, in particular, they are an important link in central mechanisms of respiratory control in adult rats when breathing air of normal composition, which does not cause disruption of gas homeostasis. It is suggested that ionotropic GABA receptors in the RTN region are involved in inhibitory modulation of neurons that regulate both the duration of the respiratory cycle phases and the level of breathing depth.
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