“This … of melatonin was partially blocked in the presence of apamin (10(-10) to 10(-7) M), a specific blocker of the small conductance calcium-… channel, but not in the presence of other potassium channel blockers like charybdotoxin (10(-8) M), glibenclamide (l0(-5) M), or tetraethylammonium (ODQ, …) M).”