Inhibitory effect of estrogen on vascular contraction from male rats of different ages

Both age and sex influence vascular contractile functions and play significant roles in cardiovascular regulation. Recent research has focused on the action of sex steroids on blood vessels and characterized both endothelium-dependent as well as-independent effects in agonists-induced contractile response. However, to study the combined influences of age and sex steroids present a complicated situation. In the current investigation, we studied the role of both these physiological factors in an in vitro approach. We found that high concentrations of estrogen (E2, 17 beta-estradiol) significantly inhibited contractile response induced by KCI in endothelium-denuded aorta derived from both young (24 wk) and aged (53 wk) male rats. The contractile responses in aorta from aged rats were significantly less than that from young adults in the absence or presence of E2 indicating that the vascular effect of E2 could be demonstrated in both young and aged male rats. Taken together, our data suggest that E2's action on endothelium-independent, KCI-induced contractile response in vitro could serve as a simple model system to examine the interaction of aging process and gender difference on vascular functions.

[Studies on mechanism of the inhibition of Ca2+/CaM PKII activity induced by hypoxia in rat hippocampal slices]

The effects of Ca2+ and ketamine on Ca2+/CaM PK II activity in rat hippocampal slices under in vitro hypoxic states have been studied and the effect of hypoxia on glutamate accumulation was also investigated. The results were as follows: (1) Ca2+/CaM PK II activity decreased gradually with increasing hypoxic time in culture medium with or without 1.3 Ca2- mmol/L, with the former case being much more pronounced. (2) Extracellular accumulation of GLU increased about two-fold after hypoxia for 30 min in vitro. (3) When slices were incubated for 30 min under conditions in excess of exogenous GLU the enzyme activity markedly decreased, a finding suggesting that the inhibition of enzyme activity induced by hypoxia may result from excitotoxicity. (4) The inhibition of the enzyme activity induced by either hypoxia or excess exogenous glutamate alone could be antagonized markedly by pretreatment with ketamine, suggesting that the hypoxia induced inhibition of the enzyme activity is mediated by NMDA receptor.

[Chemical constituents of Notopterygium incisium Ting. III: Chemical constituents isolated and identified from petroleum ether extracts of N. incisium Ting]

Six chemical compounds were isolated from the roots and rhizoma of Notopterygium incisium by column chromatography and preparative thin-layer chromatography, and identified by chemical and spectroscopic analysis as beta-sitosterol, oleic acid, linoleic acid, columbianetin, pregnenolone and ferulic acid. The presence of pregnenolone in the genus Notopterygium has not been reported.