Anticholinergic activity of the dopamine receptor agonist, TL-68 (N,N-dipropyl-2-aminotetralin)

The anticholinergic properties of a dopamine receptor agonist, a non-hydroxylated derivative of N,N-dipropylaminotetralin (TL-68), were evaluated using the guinea-pig isolated tracheal strip and rat phrenic nerve-diaphragm preparations. TL-68 competitively antagonized carbachol-induced contractions in guinea-pig trachea with a pA2 value of 5.88 +/- 0.05. In the rat phrenic nerve-diaphragm preparation, TL-68 was found to be inactive in blocking nicotinic cholinergic receptors.