AIM To elucidate the involvement of noradrenergic system in the mechanism by which diazepam suppresses basal hypothalamic-pituitary-adrenal (HPA) axis activity. METHODS Plasma corticosterone and adrenocorticotropic hormone (ACTH) levels were determined in female rats treated with diazepam alone, as well as with diazepam in combination with clonidine (α(2)-adrenoreceptor agonist), yohimbine (α...

Rats that underwent adrenal demedullation had a 93% decrease in plasma epinephrine (E) levels, but did not decrease their renal E. Even further treatment with 6-hydroxydopamine and reserpine failed to lower renal E levels. Similarly, urine E levels failed to decrease after adrenal demedullation and renal denervation. There is a renal E-synthesizing enzyme that differs from adrenal phenylethanol...

The aim of this study was to investigate the potential antidepressive-like effect of tetramethylpyrazine (TMP), one of available blood-activating and stasis-eliminating components from traditional Chinese medicines, and its mechanism of the antidepressant-like action. Forced-swimming, tail-suspension, reserpine-induced hypothermia, akinesia and ptosis, 5-hydroxytryptophan (5-HTP)-induced head-t...

Chronic renal failure (CRF) is associated with hypertension and concomitant endothelial dysfunction, enhanced vasoconstriction, and nitric oxide synthase (NOS) dysfunction. Vascular function in patients is assessed in peripheral extremity arteries like the finger arteries, whereas animal studies often use the centrally located aorta. Therefore, we examined whether peripheral tail artery and aor...

Root extracts of Rauwolfia serpentina have been used for centuries in Ayurvedic medicine as a panacea for a wide variety of physical as well as mental disorders. The potential of Agrobacterium rhizogenes-mediated genetic transformation for the synthesis of phytomolecules of high pharmaceutical value is now well established and documented. Transgenic roots were induced from R. serpentina leaf ex...

The contractile and biochemical effects of the divalent cation ionophore A23187 were studied in isolated perfused guinea pig and rat ventricles. A23187 increased both cyclic adenosine 3':5'monophosphate (cyclic AMP) and cyclic guanosine 3':5'-monophosphate (cyclic GMP) concentrations in guinea pig ventricles. Associated with these changes in nucleotide content were positive inotropic effects an...

Reserpine, on systemic administration (1) as well as after intracerebroventricular injection (2), exerts parasympathomimetic effects such as miosis, salivation, and diarrhoea. These effects have been attributed to increased central parasympathetic activity since reserpine increases the acetylcholine contents of the hy pothalamus (3). A direct parasympathomimetic action of reserpine has been exc...

Exposure of bovine chromaffin cells in primary culture to 5 microM reserpine or 25 microM forskolin results in an increase in enkephalin peptide levels within 24-48 hr; 25 microM forskolin (or cholera toxin at 50 micrograms/ml) causes a 1.5- to 2-fold increase in enkephalin peptide levels, which is maximal after 48 hr of exposure and is totally blocked by addition of cycloheximide (0.5 microgra...