Answer: Apamin is a toxin found in bee venom, and apamin can be used to study ion channels.
In 1965, apamin was first isolated from apitoxin, which is produced by the Western honey bee Apis mellifera. Apamin is a very small polypeptide, consisting of only 18 amino acids. It is the only peptide neurotoxin that is known to be permeable to the blood brain barrier (Structure-function relationships and site of action of apamin, a neurotoxic polypeptide of bee venom with an action on the central nervous system).
The primary mechanism of action of apamin is to inhibit a potassium channel called the small conductance calcium-activated potassium channel (SK channel). These SK channels are responsible for the afterhyperpolarization phase of the action potential. When apamin binds to the ion channel, the cell becomes more excitable, since potassium flow is inhibitory.
Bee venom also contains several other compounds that can cause injury or inflammation to the tissue, such as histamine and melittin.