PubMed · 3753333
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W E Thomas. 1986. Homeopathy.. https://pubmed.ncbi.nlm.nih.gov/3753333/
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Cannabinoids, the active components of marihuana, exert a variety of effects in humans. Many of these effects are mediated by binding to two types of cannabinoid receptor, CB1 and CB2. Although CB1 is located mainly in the central nervous system, it may also be found in peripheral tissues. Here, we study the effect of cannabinoids in the production of nerve growth factor by the prostate tumor cell line PC-3. We show that addition of Delta(9)-tetrahydrocannabinol to PC-3 cells stimulated nerve growth factor production in a dose-dependent and time-dependent manner. Maximal effect was observed at 0.1 microM Delta(9)-tetrahydrocannabinol and 72 h of treatment. Stimulation was reversed by the CB1 antagonists AM 251 and SR 1411716A. Pre-treatment of cells with pertussis toxin also prevented the effect promoted by Delta(9)-tetrahydrocannabinol. These results indicate that Delta(9)-tetrahydrocannabinol stimulation of nerve growth factor production in these cells was mediated by the cannabinoid CB1 receptor. The implication of Raf-1 activation in the mode of action of Delta(9)-tetrahydrocannabinol is also suggested.
BACKGROUND: Endothelin-1 (ET-1), acting mainly through the ET(A) receptor, is a potent endothelium-derived vasoconstrictor peptide. Circulating concentrations of ET-1 are increased in chronic renal failure (CRF) and may influence vascular tone. METHODS: We investigated dorsal hand vein responsiveness to local infusion of ET-1 and noradrenaline in 12 hypertensive and 12 normotensive CRF patients and in 12 age and sex matched control subjects. We also investigated dorsal hand vein responses to the ET(A) receptor antagonist, BQ-123, and the endothelium-independent vasodilator glyceryl trinitrate (GTN), in six patients with CRF. RESULTS: The dose of noradrenaline causing a 50% of maximal vasoconstriction was similar in the hypertensive (32+/-11 pmol/min) and normotensive (26+/-7 pmol/min) CRF patients and control subjects (21+/-6 pmol/min). Vasoconstriction to ET-1 (5 pmol/min) was similar in CRF patients as a whole (AUC 35+/-5%) and controls (32+/-4%; P=0.70). However, venoconstriction was significantly less in hypertensive (23+/-6%) than in normotensive CRF patients (48+/-8%; P=0.01). Overall, venoconstriction to ET-1 correlated inversely with mean arterial blood pressure in the CRF patients (R=-0.43, P=0.04). In addition, basal vein size was smaller, and plasma endothelin concentrations greater, in the hypertensive CRF group. However, infusion of BQ-123 or GTN did not cause venodilatation in these subjects. CONCLUSIONS: These studies are consistent with the hypothesis that elevated plasma ET-1 contributes to vascular tone, and elevated blood pressure, in hypertensive CRF patients, and is associated with vascular receptor downregulation consequent on the increased exposure to ET-1. The reduced vein size in CRF patients appears to be structural rather than functional in nature. Further long-term studies with endothelin antagonists are required to determine the pathophysiological role of ET-1 in the altered structure and function of blood vessels in patients with CRF.
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