Ionic Currents in Pacemaker Cells. Xanya Sofra Weiss

Prof. Dario Di Francesco, Prof. Michele Mazzanti, Dr. Andrea Barbuti, Dr. Mirko Baruscotti, Dr. Enzo Mancinelli (April 9, 2008)

Molecular Physiology and Neurobiology Unit investigates the properties of different ion channels.

A major project involves the pacemaker ("funny") channel, originally described in cardiac "pacemaker" cells of the sinoatrial node (SAN) (Brown, DiFrancesco & Noble, 1979, Nature 280, 235) and actively investigated since in cardiac myocytes and in neurons. Cardiac rhythmic activity is generated by "pacemaker" cells, which in mammals are located in the sino-atrial node. Action potentials of SAN cells have a special phase, called diastolic (or pacemaker) depolarization, which at the end of an action potential slowly takes the membrane voltage up to threshold for firing of a new action potential, thus inducing repetitive activity. Activation of If is the mechanism underlying the pacemaker depolarization. The If current is also modulated by intracellular cAMP, according to a mechanism responsible for the neurotransmitter-induced modulation of cardiac rate. A similar pacemaker current (Ih) is also expressed in neurons. In sensory neurons Ih is involved in the perception of external stimuli, or in modulating the transduction of sensory stimuli into electrical signalling. Ih is also expressed in pre-synaptic membranes, where it is involved in plasticity phenomena.

Xanya Sofra Weiss

Xanya Sofra Weiss