1 research outputs found
Modeling the differentiation of A- and C-type baroreceptor firing patterns
The baroreceptor neurons serve as the primary transducers of blood pressure
for the autonomic nervous system and are thus critical in enabling the body to
respond effectively to changes in blood pressure. These neurons can be
separated into two types (A and C) based on the myelination of their axons and
their distinct firing patterns elicited in response to specific pressure
stimuli. This study has developed a comprehensive model of the afferent
baroreceptor discharge built on physiological knowledge of arterial wall
mechanics, firing rate responses to controlled pressure stimuli, and ion
channel dynamics within the baroreceptor neurons. With this model, we were able
to predict firing rates observed in previously published experiments in both A-
and C-type neurons. These results were obtained by adjusting model parameters
determining the maximal ion-channel conductances. The observed variation in the
model parameters are hypothesized to correspond to physiological differences
between A- and C-type neurons. In agreement with published experimental
observations, our simulations suggest that a twofold lower potassium
conductance in C-type neurons is responsible for the observed sustained basal
firing, whereas a tenfold higher mechanosensitive conductance is responsible
for the greater firing rate observed in A-type neurons. A better understanding
of the difference between the two neuron types can potentially be used to gain
more insight into the underlying pathophysiology facilitating development of
targeted interventions improving baroreflex function in diseased individuals,
e.g. in patients with autonomic failure, a syndrome that is difficult to
diagnose in terms of its pathophysiology.Comment: Keywords: Baroreflex model, mechanosensitivity, A- and C-type
afferent baroreceptors, biophysical model, computational mode