Effects of some m-cholinomimetics and alpha- and beta-adrenomimetics on cyclic-AMP content of the rat submaxillary gland.

The experiments were performed on four groups of rats of both sexes, anesthetized with pentobarbital: one control and three experimental groups. The experimental group was treated with carbachol 50 micrograms/100 g, isoprenaline 10 micrograms/100 g and phenylephrine 10 micrograms/100 g, respectively. The cyclic AMP was assayed by a R.I.A. method, at 4-6 min after administration of the drugs. The salivary secretion was estimated semiquantitatively by qualifying adjectives: very copious, copious and absent. In the control group the concentration of cAMP was 699 +/- 212 p.mol/g of wet tissue; carbachol administration resulted in an important and statistically significant increase (1030 +/- 205 p.mol/g; P less than 0.001) and isoprenaline increased the cAMP concentration more than twice (1414 +/- 368 p.mol/g, P less than 0.001). Phenylephrine decreased the level of cAMP to 481 +/- 79 p.mol/g, the decrease being statistically significant (0.02 less than p less than 0.05).