Comparative effects of alinidine and propranolol in ischaemic heart disease

The role of pacemaker currents in neuropathic pain

Hyperpolarization-activated cation nonselective cyclic nucleotide-gated (HCN) channels mediate pacemaker currents that control basic rhythmic processes including heartbeat. Alterations in HCN channel expression or function have been described in both epilepsy and cardiac arrhythmias. Recent evidence suggests that pacemaker currents may also play an important role in ectopic neuronal activity that manifests as neuropathic pain. Pacemaker currents are subject to endogenous regulation by cyclic nucleotides, pH and perhaps phosphorylation. In addition, a number of neuromodulators with known roles in pain affect current density and kinetics. The pharmacology of a number of drugs that are commonly used to treat neuropathic pain includes effects on pacemaker currents. Altered pacemaker currents in injured tissues may be an important mechanism underlying neuropathic pain, and drugs that modulate these currents may offer new therapeutic options.

Exercise tolerance in angina is improved by mivazerol--an alpha 2-adrenoceptor agonist

In a double-blind, placebo-controlled, randomized trial of treadmill exercise tolerance in six patients with chronic stable angina, intravenous mivazerol 1 microgram, 2 micrograms, and 3 micrograms/kg increased the time to onset of angina by 39%, 48%, and 76%; the time to 1-mm ST depression by 36%, 76%, and 104%; and total exercise duration by 15%, 23%, and 30%, respectively. In a subsequent double-blind, placebo-controlled, randomized trial involving a further 12 patients, a single oral dose of mivazerol of 800 micrograms, 1200 micrograms, and 1600 micrograms increased the time to onset of angina by 4%, 11%, and 30%; the time to 1-mm ST depression by 33%, 43%, and 53%; and the total exercise duration by 10%, 18%, and 23%, respectively. Mivazerol is an imidazole derivative with agonist properties at the alpha 2-adrenoceptor and appears to be an effective antianginal. Mivazerol may improve exercise performance by attenuating the effects of exercise-induced sympathetic nervous system activity on the ischemic myocardium.

Effect of the combination of alinidine and other anti-anginal drugs on heart rate and blood pressure in healthy volunteers

1. Heart rate and blood pressure changes following the administration of alinidine 30 mg alone and in combination with atenolol 25 mg, nifedipine retard 20 mg and glyceryl trinitrate 500 micrograms were investigated in three groups of six healthy male volunteers. 2. Concomitant administration of alinidine and atenolol reduced (P less than 0.05) supine, standing and exercise heart rate when compared with alinidine alone. The maximum reduction in exercise heart rate was 116 +/- 2.4 beats min-1 for the combination vs 129.0 +/- 3.1 beats min-1 for alinidine alone. 3. Supine (3, 4, 8 h) and standing (2 h) systolic BP were also reduced (P less than 0.05) with the alinidine and atenolol combination compared with alinidine alone. Little change occurred in diastolic blood pressure. 4. Alinidine and nifedipine in combination reduced (P less than 0.05) the nifedipine induced increase in heart rate in the supine (2, 4 h) and standing (4 h) position and following exercise (2, 4 h). No further decreases in systolic and diastolic blood pressure occurred with the combination. 5. Alinidine administered 2 h before a glyceryl trinitrate challenge reduced (P less than 0.05) the glyceryl trinitrate induced increase in standing heart rate at all time intervals (1 to 6 min); the maximum reduction occurred at 3 min (105.0 +/- 4.3 (glyceryl trinitrate) vs 86.8 +/- 6.7 beats min-1 (combination]. Systolic blood pressure was further reduced at all time intervals with glyceryl trinitrate taken in the presence of alinidine.(ABSTRACT TRUNCATED AT 250 WORDS)