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Recently, modern scientific research has been required to understand pharmacological basis of traditional Chinese medicine (TCM) theory based on the ancient clinical experience, and to investigate the molecular mechanisms of action of Chinese herbs. Here, 20 Chinese herbs, classified into 4 properties (hot, warm, cold and cool) of TCM, were analyzed for their ability to exhibit antioxidant action, to enhance glucose uptake by murine microglia N9 cells, and to influence neurotransmitter norepinephrine (NE) release from rat pheochromocytoma PC12 cells. We found a generally protective effect of both hot/warm-natured and cold/cool-natured herbs against H₂O₂-induced N9 cell death, partially by elevating superoxide dismutase (SOD) activity. Glucose uptake was elevated after treatment with some hot/warm-natured herbs. In addition, most herbs with hot/warm nature tended to stimulate NE release, while such stimulatory effect was not observed in the herbs with cold/cool nature. Two cold/cool-natured herbs, Rhizoma coptidis and Radix scutellariae, even significantly suppressed the release. These results suggest that the distinct abilities of Chinese herbs to regulate neural cell functions appear to be correlated with their natures identified in traditional TCM theory, and may be a useful guide for their utility in neural degenerative diseases.

Radix astragali is a herbal remedy used in China to treat patients with diabetes exposed to repeated episodes of hypoglycemia. The physiological basis or validity of this approach is not clear. In the present study, we examine the effect of pre-treatment with Radix astragali on hormonal counterregulatory responses to hypoglycemia in normal male Sprague-Dawley rats. Four groups of rodents were studied. In two of these groups, rodents were pre-treated for 3 days with either intravenous Radix astragali or control solution and, subsequently, while awake and unrestrained, underwent an in vivo hyperinsulinemic hypoglycemic (50 mg/dl) clamp study. The rodents in other two groups were pre-treated for 7 days with either intravenous Radix astragali or control solution. In addition, for the last 3-days of their treatment, the rats were subjected to a once-daily episode of insulin-induced hypoglycemia. Upon completion of this protocol, each rat underwent a controlled in vivo hyperinsulinemic hypoglycemic (50 mg/dl) clamp study. Radix astragali was shown to amplify the glucose counterregulatory response to hypoglycemia in both untreated and recurrently hypoglycemic rats. Immunocytochemistry studies suggested this might reflect increased neural activation in two key central glucose-sensing regions, the paraventricular hypothalamus and the nucleus tractus solitarius. Based on these rodent studies, we conclude that Radix astragali pre-treatment can amplify the counterregulatory response to hypoglycemia through a mechanism that may involve the central glucose-sensing regions. Future studies to examine the potential therapeutic benefit of Radix astragali in rodent models of type 1 diabetes are warranted.

Processing of information into long-term storage (consolidation of memory) and the retrieval of processed knowledge is not independent of the physiological state of animal and man. The neuroendocrine system which is composed of central nervous and peripheral components i.e., peptidergic neurons and forming of membrane-active steroids in the brain, on the one hand, and releasing hormones into the circulation, on the other hand, is the primary messenger of bodily states. The neuroendocrine system is a rapidly responding one to environmental changes and, in turn, assures optimal conditions for processing information into long-term storage. Retrieval of knowledge is then affected either by pro-active influence of neuroendocrine principles during learning and consolidation or by a simple presence (tonic actions) during retrieval. These general conclusions can be drawn from studies devoted to the mnemonic effects of circulating adreno-sympathetic catecholamines epinephrine and norepinephrine, adrenal corticosteroids and (neuro) peptide vasopressin. The action of these hormones is of central nervous nature via direct or indirect mechanisms involving the central nucleus of the amygdala and the hippocampus as major targets.