24 research outputs found
Hemodynamic and clinical limitations of long-term inotropic therapy with amrinone in patients with severe chronic heart failure.
On the theory of reflection from a wire grid parallel to an interface between homogeneous media
Theoretical calculation of transition energies of low-lying electronic states of the CuCl molecule
Differential Effect of ?-Adrenergic Stimulation on the Frequency-Dependent Electrophysiologic Actions of the New Class III Antiarrhythmics Dofetilide, Ambasilide, and Chromanol 293.
Pharmacological comparison of the effect of ibogaine and 18-methoxycoronaridine on isolated smooth muscle from the rat and guinea-pig
1. Ibogaine and 18-methoxycoronaridine are naturally occurring alkaloids reported to possess antiaddictive properties in several models of drug dependence. We have examined their effect at μ-opioid receptors regulating neurogenic contractions of several smooth muscle preparations and also against spontaneous contractions of the rat isolated portal vein. 2. Ibogaine (pIC(50) 5.28) and 18-methoxycoronaridine (pIC(50) 5.05) caused a concentration-dependent inhibition of cholinergic contractions of the guinea-pig ileum which was not affected by the opioid receptor antagonist naloxone (1 μM). 3. In the rat isolated vas deferens ibogaine and 18-methoxycoronaridine caused a concentration-dependent enhancement of purinergic contractions. Both agents (30 μM) caused a 3–5 fold rightward displacement of DAMGO-induced inhibition of purinergic contractions, but similar effects were observed for ibogaine against α(2)-adrenoceptor-mediated inhibition of neurogenic responses. 4. In the guinea-pig isolated bladder both ibogaine (10 μM) and 18-methoxycoronaridine (10 μM) caused a 2 fold increase in the purinergic component of neurogenic contractions without significantly altering cholinergic contractions or responses to exogenous ATP. In contrast, ibogaine (1–30 μM), but not 18-methoxycoronaridine, caused a concentration-dependent enhancement of spontaneous contractions of the rat isolated portal vein. 5. In summary, while ibogaine and 18-methoxycoronaridine modulated electrically-evoked contractions in the three preparations examined, we have no evidence for a selective interaction with pre-junctional μ-opioid receptors. The pronounced enhancement of purinergic contractions produced by both agents is a novel finding and worthy of further investigation