In this study the effect of adrenergic receptor agonists and antagonists on physostigmine induced yawning was investigated. Intraperitoneal injection of different doses of physostigmine (0.03, 0.05, 0.1 and 0.2 mg/kg) caused yawning in white rats. The greatest response was seen at a dose of 0.2 mg/kg physostigmine. Phenylephrine, an α1 agonist, and clonidine, an α2 agonist, led to a decrease in...

Diabetic neuropathy is the loss of sensory function beginning distally in lower extremities, which also characterized by pain and substantial morbidity. Furthermore, locus coeruleus (LC) nucleus has been proposed to play an important role descending control through activation α2-noradrenergic (NA) receptors spinal dorsal horn. We studied, on diabetic mice, effect electrical stimulation LC tacti...

Two decades of investigations have failed to unequivocally clarify the functions and the molecular nature of imidazoline-2 receptors (I2R). However, there is robust pharmacological evidence for the functional modulation of monoamino oxidase (MAO) and other important enzyme activities by I2 site ligands. Some compounds of this class proved to be active experimental tools in preventing both exper...

Radiocontrast nephropathy (RCN) is a common clinical problem for which there is no effective therapy. Utilizing a murine model, we tested the hypothesis that alpha(2)-adrenergic receptor agonists (clonidine and dexmedetomidine) protect against RCN induced with iohexol (a nonionic low-osmolar radiocontrast). C57BL/6 mice were pretreated with saline, clonidine, or dexmedetomidine before induction...

Neurons in the paraventricular nucleus (PVN) that project to the brain stem and spinal cord are important for autonomic regulation. The excitability of preautonomic PVN neurons is controlled by the noradrenergic input from the brain stem. In this study, we determined the role of alpha(2) adrenergic receptors in the regulation of excitatory and inhibitory synaptic inputs to spinally projecting P...

The present study demonstrates that agonist-mediated activation of α2A adrenergic receptors (α(2A)AR) is voltage-dependent. By resolving the kinetics of conformational changes of α(2A)AR at defined membrane potentials, we show that negative membrane potentials in the physiological range promote agonist-mediated activation of α(2A)AR. We discovered that the conformational change of α(2A)AR by vo...

65 The decreased sensitivity to clonidine would appear to be an important and reversible sign of withdrawal in the guinea-pig ileum. Such interactions between opiate receptors and a-adren-ergic receptors do not appear to occur in the mouse vas deferens (Gillan et al., 1979). However, vasa deferentia from rats treated chronically with clonidine showed lower sensitivity to the inhibitory effects ...

Recent studies have shown that NMDA receptors are involved in the tolerance and dependence to opioids. In addition, it has been reported that ketamine, dextromethorphan and amantadine have antagonistic activity at NMDA receptors. Therefore, this study was conducted to clarify the effect of these drugs on morphine withdrawal syndrome. Morphine dependence was induced by increasing doses of morphi...

The role of adrenergic agents in augmenting proximal tubular salt and water flux, was studied in a preparation of freshly isolated rabbit renal proximal tubular cells in suspension. Norepinephrine (NE, 10(-5) M) increased sodium influx (JNa) 60 +/- 5% above control value. The alpha adrenergic antagonist, phentolamine (10(-5) M), inhibited the NE-induced enhanced JNa by 90 +/- 2%, while the beta...