KATP channel exists as an octameric complex, containing two types of proteins subunits Consists of 4 inwardly rectifying K+ channel subunits , each associated with a larger regulatory sulphonylurea receptor (SUR). Inhibited by mM [ATP]i and sulphonylurea agents Activated by nucleotide diphosphates, in the presence of Mg2+ Endogenous vasodilators, such as calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) are mediated through PKA mediated activity of KATP channels.