piperidines and Coronary-Vasospasm

The efficacy of 5-hydroxytryptamine 1B/1D (5-HT 1B/1D) agonists is related to their inhibitory effects on neurogenic inflammation, mediated through serotoninergic control mechanisms. Recently, a series of oral second generation 5-HT 1B/1D agonists (eletriptan, naratriptan, rizatriptan and zolmitriptan) have been developed and are reviewed in this paper. Their in vitro and in vivo pharmacological properties, clinical efficacy, drug interactions, and adverse effects are evaluated and compared to the gold standard in the treatment of acute migraine, sumatriptan.

Topics: Acute Disease; Animals; Clinical Trials as Topic; Coronary Circulation; Coronary Vasospasm; Drug Design; Drug Interactions; Humans; Inactivation, Metabolic; Indoles; Meninges; Migraine Disorders; Molecular Structure; Nociceptors; Oxazoles; Oxazolidinones; Piperidines; Propranolol; Pyrrolidines; Randomized Controlled Trials as Topic; Rats; Receptor, Serotonin, 5-HT1B; Receptor, Serotonin, 5-HT1D; Receptors, Serotonin; Recurrence; Serotonin Receptor Agonists; Structure-Activity Relationship; Sumatriptan; Treatment Outcome; Triazoles; Tryptamines; Vasoconstrictor Agents

This study was designed to test the hypothesis of a possible role of serotonin in the pathogenesis of myocardial ischemia in patients with pure vasospastic angina, since serotonin is known to cause contraction in isolated coronary arteries. This effect, as well as serotonin-induced platelet aggregation, is reversed by ketanserin, a specific S2-receptor blocker. Five male patients (49 to 68 years old) with more than six episodes/day of myocardial ischemia at rest as characterized by ST segment elevation on the electrocardiogram (ECG) were selected for the study after a 2 day run-in period of continuous ECG Holter monitoring in the absence of any therapy except that with sublingual nitrates. In a double-blind crossover protocol they received consecutive infusions of 6 hr each of ketanserin (2 mg/hr iv, preceded by a 10 mg bolus in three patients) and placebo in the following sequence: ketanserin-placebo-ketanserin-placebo in the first and placebo-ketanserin-placebo-ketanserin in the second 24 hr period. The efficacy of the infused drug was tested by exposing platelet-rich plasma, obtained from the study patients at a fixed morning time before and during ketanserin infusions, to a series of serotonin concentrations from 10(-5) to 10(-8)M in a conventional aggregometer. A complete suppression of aggregation curves in the range of serotonin concentrations tested resulted during administration of ketanserin. The efficacy of the drug in preventing ischemic episodes was assessed by computing the ischemic episodes (recorded by Holter monitoring) and nitroglycerin consumption in each 6 hr ketanserin period and in the corresponding placebo period. A total of 171 ischemic episodes were recorded, 33 of which (19%) were symptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Angina Pectoris, Variant; Coronary Disease; Coronary Vasospasm; Double-Blind Method; Drug Evaluation; Hemodynamics; Humans; Ketanserin; Male; Middle Aged; Piperidines; Placebos; Platelet Aggregation; Serotonin; Serotonin Antagonists

Coronary artery bypass graft (CABG) surgery is hampered by deleterious vasospasm in the vessel wall, especially in vein grafts. Endothelin (ET) is a strong vasoconstrictor that can be observed in increasing concentrations during CABG surgery.. Endothelin-induced vasoconstriction was evaluated in isolated, endothelium-denuded vessel segments of the human saphenous vein (SV), left internal mammary artery (LIMA), and coronary arteries. The ET(A) and ET(B) receptor mRNA levels were quantified by real-time polymerase chain reaction (PCR) analysis.. The ET(A) and ET(B) receptor mRNA levels were significantly higher in the SV than in the LIMA and the coronary arteries. ET-1 induced a more efficacious contraction in the SV and LIMA as compared with in the coronary arteries. The ET(B) receptor agonist, Sarafotoxin 6c (S6c) stimulated constriction of the LIMA and SV, while inactive in the coronary arteries. The concentration-response curve for S6c was biphasic, suggesting activation of ET(A) receptors at high concentrations as this response could be inhibited by FR139317 (10 micromol/L), and ET(B) at low concentrations as this response could be inhibited by BQ788 (0.1 micromol/L).. Endothelin-induced vasoconstriction is mediated by ET(A) receptors alone in coronary arteries, while a combination of ET(A) and ET(B) receptors are of importance in SV and LIMA. Expression of contractile ET(B) receptors may be a pharmacologic disadvantage that contributes to the vasospasm during CABG surgery. The lower levels of ET(A) and ET(B) receptor mRNA in the LIMA and coronary arteries as compared with in the SV may provide one explanation for the better long- and short-term patency of LIMA as compared with SV grafts.

Topics: Adult; Aged; Aged, 80 and over; Azepines; Coronary Artery Bypass; Coronary Vasospasm; Coronary Vessels; Culture Techniques; Endothelin Receptor Antagonists; Endothelium, Vascular; Female; Humans; Indoles; Male; Middle Aged; Myocardial Revascularization; Oligopeptides; Piperidines; Receptor, Endothelin A; Receptor, Endothelin B; Receptors, Endothelin; Vasoconstriction; Vasoconstrictor Agents; Veins; Viper Venoms

Because ergonovine appears to produce coronary contractions by a serotonergic (5-HT) mechanism, we attempted to prevent ergonovine-induced ischemia in patients with vasospastic angina by pretreatment with ketanserin, a new selective 5-HT blocker. We studied seven patients with consistently positive results of ergonovine testing (ST segment elevation in three and ST segment depression in four). Ergonovine testing was performed before and after a bolus of 10 mg of ketanserin (all patients) and infusion of 2 to 4 mg/hr for 8 hr (six patients). To assess 5-HT blockade during ketanserin infusion, the constrictor response of hand veins to 5-HT was tested before and after ketanserin. Despite evidence of 5-HT blockade in hand veins, ergonovine-induced ischemia was not prevented by ketanserin in any patient, and there was no significant change in the dose of ergonovine required to provoke ischemia. In one patient, four spontaneous episodes of ST segment elevation occurred during infusion of ketanserin. The plasma concentrations of ketanserin at the time of ergonovine testing ranged from 61 to 127 ng/ml (mean 102) and were well above those that completely inhibit canine coronary 5-HT contractions in vitro. Although human coronary arteries may differ in their responsiveness to 5-HT or ketanserin, these data suggest that ischemia from ergonovine-induced coronary vasospasm is not mediated by 5-HT receptors.

Topics: Aged; Angina Pectoris; Coronary Vasospasm; Coronary Vessels; Ergonovine; Hand; Humans; Ketanserin; Male; Middle Aged; Piperidines; Receptors, Serotonin; Serotonin Antagonists; Vasoconstriction