Cardiovascular effects of substituted tetrahydroisoquinolines in rats.

Abstract

1. A series of substituted tetrahydroisoquinolins derived from the cleavage products of tetrandrine were found to inhibit [3H]-nitrendipine binding to rat cerebral cortical membranes. Those compounds which displaced [3H]-nitrendipine binding were also able to inhibit high KCl-induced contraction of rat aorta in vitro. 2. There was a significant correlation between the ability of these tetrahydroisoquinolines to inhibit [3H]-nitrendipine binding and KCl-induced contraction (r = 0.99, P less than 0.001). 3. CPU-23 (1-(1-[(6-methoxy)-naphth-2-yl])-propyl-2-(1-piperidine)-acetyl- 6,7- dimethoxy-1,2,3,4-tetrahydroisoquinoline), one of the most potent compounds identified in this series, behaved as a simple competitive inhibitor at the [3H]-nitrendipine binding site and reduced the apparent affinity but not the maximal number of binding sites in saturation analysis. 4. In contrast to nifedipine which caused hypotension and tachycardia, CPU-23 induced both hypotension and bradycardia in a dose-dependent manner in pentobarbitone-anaesthetized Sprague-Dawley rats, spontaneously hypertensive and age-matched normotensive WKY rats. 5. It is suggested that CPU-23 may exert its cardiovascular effects via interaction with the dihydropyridine binding site on the L-type calcium channel.

• Authors: H Dong, C M Lee, W L Huang, S X Peng
• Journal: British journal of pharmacology (Br J Pharmacol) Vol. 107 Issue 1 Pg. 262-8 (Sep 1992) ISSN: 0007-1188 [Print] England
• PMID: 1330162 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Alkaloids
• Benzylisoquinolines
• Calcium Channels
• Isoquinolines
• Piperidines
• Tetrahydroisoquinolines
• CPU 23
• tetrandrine
• Potassium Chloride
• Nitrendipine

Topics

• Alkaloids (metabolism, pharmacology)
• Animals
• Aorta
• Benzylisoquinolines
• Blood Pressure (drug effects)
• Calcium Channels (drug effects)
• Cerebral Cortex (drug effects, metabolism)
• Dose-Response Relationship, Drug
• Female
• Heart Rate (drug effects)
• Hypertension (physiopathology)
• Isoquinolines (metabolism, pharmacology)
• Male
• Nitrendipine (metabolism)
• Piperidines (metabolism, pharmacology)
• Potassium Chloride (pharmacology)
• Rats
• Rats, Inbred SHR
• Rats, Sprague-Dawley
• Rats, Wistar
• Tetrahydroisoquinolines
• Vasoconstriction (drug effects)