Contractile effect of succinylpurines on guinea pig uterus

1. The effects of adenosine analogues on isolated guinea pig uterus were studied in vitro. 2. Low concentrations of adenosine analogues contracted guinea pig uterus. The relative potencies of contractive effect were adenosine greater than AMP greater than ADP greater than ATP greater than 2-chloroadenosine greater than N6-phenylisopropyl-adenosine (PIA) greater than 5'-N-ethylcarboxamidoadenosine (NECA) greater than adenylosuccinate greater than succinyladenosine. 3. Pretreatment of the uterus strips with theophylline blocked the action of adenosine. However, dipyridamole did not impair the adenosine actions. 4. The role of naturally occurring adenosine analogues was discussed.