Effect of a specific tetrahydroisoquinoline on the blood pressure in animals.

1-(2-Methyl-3-hydroxy-5-hydroxymethyl-4-pyridyl)-6,7-dihydroxy-1,2, 3,4-tetrahydroisoquinoline (PTIQ) when injected into anesthetized normotensive minipigs and dogs lowers the arterial blood pressure in a dose-related manner. The blood pressure lowering effect of PTIQ is greater on minipigs than dogs at comparable dose levels. The heart rate is generally slower after PTIQ was injected than the control.