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Effects of the Calcitonin Gene‐Related Peptide (CGRP) Receptor Antagonist BIBN4096BS on α‐CGRP‐Induced Regional Haemodynamic Changes in Anaesthetised Rats
Author(s) -
Arulmani Udayasankar,
Schuijt Martin P.,
Heiligers Schuijt,
Willems Heiligers,
Villalón Carlos M.,
Saxena Pramod R.
Publication year - 2004
Publication title -
basic and clinical pharmacology and toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.805
H-Index - 90
eISSN - 1742-7843
pISSN - 1742-7835
DOI - 10.1111/j.1742-7843.2004.pto940606.x
Subject(s) - calcitonin gene related peptide , vasodilation , medicine , endocrinology , antagonist , calcitonin , hemodynamics , vascular resistance , receptor , neuropeptide , pharmacology
Several studies suggest that a calcitonin gene‐related peptide (CGRP) receptor antagonist may have antimigraine properties, most probably via the inhibition of CGRP‐induced cranial vasodilatation. We recently showed that the novel selective CGRP receptor antagonist, BIBN4096BS (1‐piperidinecarboxamide, ‐N‐[2‐[[5‐amino‐1‐[[4‐(4‐pyridinyl)‐1‐piperazinyl] carbonyl] pentyl]amino]‐1‐[(3,5‐dibromo‐4‐hydroxyphenyl) methyl]‐2‐oxoethyl]‐4‐(1,4‐dihydro‐2‐oxo‐3(2H)‐quinazolinyl)‐, [[R‐(R,(R*,S*)]), attenuated the CGRP‐induced porcine carotid vasodilatation in a model predictive of antimigraine activity. In order to evaluate the potential safety of BIBN4096BS in migraine therapy, this study was designed to investigate the effects of intravenous BIBN4096BS on α‐CGRP‐induced systemic and regional haemodynamic changes in anaesthetised rats, using radioactive microspheres. In vehicle‐pretreated animals, consecutive intravenous infusions of α‐CGRP (0.25, 0.5 and 1 μg kg −1 min. −1 ) dose‐dependently decreased mean arterial blood pressure with an accompanying increase in heart rate and systemic vascular conductance whereas cardiac output remained unchanged. α‐CGRP also increased the vascular conductance to the heart, brain, gastrointestinal tract, adrenals, skeletal muscles and skin, whilst that to the kidneys, spleen, mesentery/pancreas and liver remained unaltered. The above systemic and regional haemodynamic responses to α‐CGRP were clearly attenuated in BIBN4096BS (3 mg kg −1 intravenously)‐pretreated animals. These results indicate that exogenously administered α‐CGRP dilates regional vascular beds via CGRP receptors on the basis of the antagonism produced by BIBN4096BS. Moreover, the fact that BIBN4096BS did not alter baseline haemodynamics suggests that endogenously produced CGRP does not play an important role in regulating the systemic and regional haemodynamics under resting conditions.