Most members of the TRP channel family are permeable to Ca2+. Although TRPM4 and 5 can be activated by increased levels of intracellular Ca2+, they are impermeable to it. Instead, they are monovalent-selective with highest affinity for Na+ transport, of which leads to depolarization of the membrane (Launay et al. 2002, Prawitt et al. 2003). They play a central role in cardiomyocytes, neurons, endocrine pancreas cells, kidney epithelial cells and cochlea hair cells.
sodium channel activity of TRPM4,5 [plasma membrane]