Role of the Interaction of Ionic Currents with Na/K Pump in Neuromodulation of Bursting Activity

Role of the Interaction of Ionic Currents with Na/K Pump in Neuromodulation of Bursting Activity

By using a full biophysically accurate and reduced models of single heart interneurons, we identify how changes of proportions between Na/K (IPump), hyperpolarization activated(Ih), and persistent Na (IP) currents affect trends of changes of bursting patterns by modulation of one or simultaneous comodulation of two of these currents. Finding the oscillatory states of one- and two-parameter variations allows us to study changes to bursting patterns. Bursting period, spike frequency, amplitude, and burst and interburst durations are measured from the oscillatory regimes representing the bursting activity of the full system. In the 2D model, we consider the map (Gh, IPumpMax) to simulate the application of myomodulin to a biological neuronal circuit. There was a maximum burst duration which indicated 2 different mechanisms of speeding up bursting activity. In the biophysically accurate 15D model, upmodulating GP lead to episodic seizure-like bursting at low values of IPumpMax. In general, upmodulating IPumpMax shortened burst duration and inter-burst intervals, but with certain larger values of GP the burst duration grows with IPumpMax.