The insulinotropic activity of the imidazoline derivative RX871024 was compared in pancreatic islets from nondiabetic Wistar rats and spontaneously diabetic Goto-Kakizaki (GK) rats. RX871024 significantly stimulated insulin secretion in islets from both animal groups. The insulinotropic activity of RX871024 was higher than that of the sulfonylurea glibenclamide. This difference was more pronoun...

AIM To investigate whether agmatine could selectively block a given type of the voltage-gated calcium channels (VGCC) and whether related receptors are involved in the blocking effect of agmatine on VGCC. METHODS The whole-cell patch recording technique was performed to record VGCC currents in the cultured neonatal rat hippocampal neurons. RESULTS Verapamil (100 micromol/L), a selective blo...

1 The hypotensive effect of imidazoline-like drugs, such as clonidine, was attributed both to alpha2-adrenergic receptors and nonadrenergic imidazoline receptors, which are divided into I1, I2 and I3 subtypes. 2 We have recently synthesized a derivative of (2-(2-chloro-4-iodo-phenylamino)-5-methyl-pyrroline (LNP 911), the first high-affinity and selective ligand for I1 receptors (I1R), with a p...

BACKGROUND Platelet alpha(2A)-adrenoceptors (alpha(2A)AR) and imidazoline binding sites (subtype I(1)) have been proposed as peripheral markers of brain stem receptors that mediate sympathetic outflow and are reported to be elevated in major depression. METHODS In our study, p[(125)I]-iodoclonidine was used to assess platelet alpha(2A)AR and I(1) binding sites in healthy postmenopausal women ...

Macrophages are key responders of inflammation and are closely related with oxidative stress. Activated macrophages can enhance oxygen depletion, which causes an overproduction of reactive oxygen species (ROS) and leads to further excessive inflammatory response and tissue damage. Agmatine, an endogenous metabolite of L-arginine, has recently been shown to have neuroprotective effects based on ...

The nature of the binding site(s) involved in the insulin secretory activity of imidazoline compounds remains unclear. An imidazoline I2 binding site (I2BS) has been neglected since the classic I2 ligand, idazoxan, does not release insulin. Using the rabbit as an appropriate model for the study of this type of binding sites, we have tried to re-evaluate the effects of idazoxan, the selective I2...

Our previous study showed that rilmenidine, a selective I(1)-imidazoline receptor agonist, enhanced the phosphorylation of mitogen-activated protein kinase (MAPK)(p42/44), via the phosphatidylcholine-specific phospholipase C pathway in the pheochromocytoma cell line (PC12). In the present study, we tested the hypothesis that enhancement of MAPK phosphorylation in the rostral ventrolateral medul...

PURPOSE Brimonidine is an imidazoline compound used for the treatment of glaucoma, but having very little effect on pupil diameter. Like para-aminoclonidine, most imidazoline compounds interact with postsynaptic α-adrenoceptors and cause pupil dilatation. Therefore, as part of an investigation of the mechanism of action of brimonidine on pupil diameter, the present study was initiated to measur...

1 Atipamezole (4-(2-ethyl-2,3-dihydro-1H-inden-2-yl)-1H-imidazole) was first introduced as a potent and specific alpha2-adrenoceptor antagonist, but in some tissues [3H]atipamezole identifies an additional population of binding sites, distinct from both classical alpha2-adrenoceptors and I1- and I2-imidazoline receptors identified with [3H]para-aminoclonidine or [3H]idazoxan. 2 In the present s...

Liver fibrosis is a global health problem and its relationship with imidazoline I2 receptor has not been reported. This study aimed to investigate the effects and underlying mechanisms of imidazoline I2 receptor (I2R) inhibitor idazoxan (IDA) on carbon tetrachloride (CCl4)-induced liver fibrosis. In vivo liver fibrosis in mice was induced by intraperitoneally injections of CCl4 for eight weeks,...