In-vivo binding of (+)-[3H]PN 200-110 to peripheral tissues and brain of spontaneously hypertensive rats: Effect of lacidipine

T. Mennini, C. Taddei, A. Uslenghi, A. Cagnotto, D. Micheli, D. Trist, G. Gaviraghi, E. Ratti

Research output: Contribution to journalArticlepeer-review

Abstract

The time-course of dihydropyridine receptor occupancy by lacidipine and its relationship with pharmacological activity has been studied in spontaneously hypertensive rat {(SHR), as measured by the inhibition of specific (+)-[3H]PN 200-110 binding in-vivo. After oral administration of doses active in reducing blood pressure, lacidipine did not show tissue target differences in respect to binding sites labelled by(+)-[3H]PN200-110 in cerebral cortex,heart,ileum,bladder and thoracic aorta. The relative occupancy of receptors in heart 60 min after oral administration of 1 mg kg-1 lacidipine was 75%. After 12 h, when lacidipine was still effective in reducing blood pressure in SHR, a low (15%) but detectable proportion of receptors was still occupied by the drug. The percentage decrease of blood pressure was linear with the percentage of receptor occupancy obtained by different doses of lacidipine, that is, there was a close correspondence between ED25 for decrease in blood pressure (0.33 mg kg-1) and ED25 for inhibition of (+)-[3H]PN 200-110 specific binding in the heart (0.36 mg kg-1). The long-lasting effect of lacidipine on blood pressure might be explained by its selective interaction with dihydropyridine binding sites labelled in vivo by (+)-[3H]PN 200-110.

Original languageEnglish
Pages (from-to)430-433
Number of pages4
JournalJournal of Pharmacy and Pharmacology
Volume45
Issue number5
Publication statusPublished - 1993

ASJC Scopus subject areas

  • Pharmaceutical Science
  • Pharmacology

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