細胞外ATPの存在とその薬理作用および代謝

シグナル伝達と細胞機能調節

抄録

Cells are equipped with complex mechanisms for synthesis of ATP and try to keep the intracellular level of this compound, which is indispensable for maintenance of normal function and integrity, as constant as possible. Thus, it is generally believed that ATP rarely cross the plasma membrane of viable cells. However, since the first report of Holton in 1959, the release of nucleotides from cells has become an established fact, and the physiological role and metabolism of the released ATP has become an important topic; potent actions of extracellular purine nucleotides and nucleosides have been recognized for many years. In 1972, Burnstock demonstrated that ATP has a transmitter role in certain types of nerves and proposed a concept of purinergic nerve. The receptor for purine nucleotides, designated as P₂, as opposed to P₁, by Burnstock in 1978 was further subclassified in 1985 into P_2X and P_2Y by himself, and we now have a train of P₂ receptors, such as P_2S, P_2T, P_2Z and so forth. In this review, I summarized the characteristics of these purinoceptors. Pharmacological effects and metabolism of extracellular nucleotides were discussed and a brief mention was made of ecto-nucleotidases.