OBJECTIVES We studied the effects of clonidine on cardiac sympathetic activity and left ventricular function in patients with congestive heart failure (CHF). BACKGROUND Sympathetic activation has major prognostic implications in patients with heart failure. Clonidine, an imidazoline and alpha2-receptor agonist, has been shown to cause a reduction in generalized sympathetic activity. METHODS...

A partial recovery of locomotor functions has been shown in spinal cord-transected (Tx) cats after regular treadmill training and repeated administration of clonidine, an alpha(2)-adrenoreceptor agonist. However, clonidine has generally failed to show prolocomotor effects in other models (e.g., rat or mudpuppy in vitro-isolated spinal cord preparations). The reasons for this discrepancy remain ...

It has been indicated that activation of peripheral imidazoline I2-receptor (I-2R) may reduce the blood pressure in spontaneously hypertensive rats (SHRs). Also, guanidinium derivatives show the ability to activate imidazoline receptors. Thus, it is of special interest to characterize the I-2R using guanidinium derivatives in blood vessels for development of antihypertensive agent(s). Six guani...

Heart Failure To the Editor: We read with great interest the paper by Swedberg et al.1 With respect to it, we will supply additional information that might aid in the understanding of the failure of imidazoline’s agonists to improve chronic congestive heart failure (CCHF) in patients. We have assessed all plasma neurotransmitters in some 30 000 normal and diseased subjects. Included were noradr...

Non-adrenergic ligands that bind to imidazoline receptors (I-R), a selective ligand that binds to alpha2-adrenoceptors (alpha2-AR) and mixed ligands that bind to both receptors were tested for their action on water intake behavior of 24-h water-deprived rats. All drugs were injected into the third cerebral ventricle. Except for agmatine (80 nmol), mixed ligands binding to I-R/alpha2-AR such as ...

The imidazoline compounds may produce mydriasis after systemic administration to some species (rats, cats, and mice). In mydriatic activity of imidazolines, α2D-adrenoceptors subtype(s) seems to be involved. In this study, the pupil dilatory effect evoked by 2 newly synthesized imidazoline derivatives-α2-adrenoceptor agonists: marsanidine and 7-methylmarsanidine-was compared. The compounds were...

C lonidine is an imidazoline derivative with antihypertensive properties. Its mode of action is complex and is as yet not fully understood. Some datal-‘j indicate that an action on the central nervous system, predominantly at bulbar and diencephalic levels, causes a decreased sympathetic outflow to the cardiovascular system. Other studies’ show a direct peripheral effect as well. Since the intr...

Chronic stimulation of sympathetic nervous activity contributes to the development and maintenance of hypertension, leading to left ventricular hypertrophy (LVH), arrhythmias and cardiac death. Moxonidine, an imidazoline antihypertensive compound that preferentially activates imidazoline receptors in brainstem rostroventrolateral medulla, suppresses sympathetic activation and reverses LVH. We h...