Calcium channel blockers inhibit Kappa opioid withdrawal induced jejunum contractions

Abstract

A study was carried out to assess and compare the effect of nimodipine, nifedipine, verapamil and diltiazem on the naloxone induced U-50, 488H withdrawal contractions in the isolated rabbit jejunum. Single concentration of L-type calcium channel blocker was added one minute before the addition of naloxone to induce the withdrawal response in U-50,488H dependent jejunum segment. All studied L-type calcium channel blockers were dose dependently and significantly (P < 0.05) inhibited the withdrawal contractions at different molar concentrations range. The negative log IC50 value of nimodipine, nifedipine, verapamil and diltiazem was found to be 8.80 ± 0.18, 8.00 ± 0.28, 7.25 ± 0.17 and 6.95 ± 0.24, respectively. Nimodipine, nifedipine, verpamil and diltiazem dose dependently inhibit U-50, 488H withdrawal induced contractions in the isolated rabbit jejunum. Nimodipine was found to be significantly more potent among others. © APTI.