@article{oai:niigata-u.repo.nii.ac.jp:00025958,
 author = {Satoh, Hiroyasu and Nakatani, Toshiaki},
 issue = {1},
 journal = {新潟歯学会雑誌, 新潟歯学会雑誌},
 month = {Aug},
 note = {Electrophysiological and mechanical effects of nicotine in the right and left atrial muscles of rat were investigated. Nicotine (300μM and 1mM) decreased the action potential amplitude (APA). The resting potential (RP) was depolarized. The action potential duration (APD, at 90% repolarization) of the right atrium was prolonged, whereas the APD of the left atrium was shortened. The responses were concentration-dependent. In the right atrium, nicotine prolonged the cycle length. Nicotine (10μg to 1mg) caused a negative inotropic effect in both the right and left atria in a concentration-dependent manner. The responses were potentiated with an increase in the frequencies of stimulation (0.5 to 3Hz). Nicotine caused more potent depressant effects on the right atrium than on the left atrium. The effects were not modified by atropine (1μM) and hexamethonium (lmM). Addition of isoproterenol (2μM) recovered the depressed action potentials induced by nicotine (300μM). The responses were reversible. These results indicate that nicotine causes only the negative responses on rat atria due to its direct action, and suggest that the differences between the electrophysiological and mechanical effects of nicotine on the right and left atria would result from physiological and anatomical properties of rat atria., ウイスター系ラット左右心房筋を用いて,ニコチンによる電気生理学的作用と機械的作用について調べた。ニコチン(300μm-1mM)は活動電位振幅を抑制し,静止膜電位を脱分極した。活動電位持続時間は右心房筋では延長し,左心房筋では短縮した｡右心房筋では自発興奪の頻度を抑制した｡また,左右心房筋で陰性変力作用を示し,左心房筋の抑制作用は刺激頻度(0.5-1Hz)に依存した。3Hzで刺激の左心房筋と比較して,右心房筋(約200回/分)の方が強い抑制作用を出現した。これらの反応は濃度依存性に出現し,正常タイロード液に戻すと完全に回復した。アトロピン(1μM)やヘキサメトニウム(1mM)前処置によるニコチン反応への影響はなかった。さらに,ニコチンによる抑制作用はイソプロテレノール(2μM)投与によって拮抗された｡以上の結果により,ニコチンは陰性変時変力作用をその心筋膜への直接作用によって引き起こすことを明らかにした｡また,左右心房筋に対する反応の違いはその生理学解剖学的特性の差異から発現されるのではないかと考えられた｡},
 pages = {1--7},
 title = {Nicotine actions on the action potentials and the contractile force in the rat atrial muscles : Comparison between the right and left atria},
 volume = {25},
 year = {1995}
}