dopamine (da) is one of the main catecholamines in the brain and is crucial for movement coordination, endocrine function, reward, mood, memory and emotions. the dopaminergic system is the primary therapeutic target in the treatment of parkinson’s disease (pd), drug addiction and schizophrenia. notwithstanding, dysfunction of central dopaminergic neurotransmission has also been associated to de...

Nicotinamide, the amide derivative of vitamin B(3), cooperates with retinoic acid (RA), a form of vitamin A, and 1,25-dihydroxyvitamin D(3) (D3), to regulate cell differentiation and proliferation of human myeloblastic leukemia cells. In human myeloblastic leukemia cells, RA or D3 are known to cause MAPK signaling leading to myeloid or monocytic differentiation and G0 cell cycle arrest. In this...

D3 receptors act synergistically with D1 receptors to inhibit sodium transport in renal proximal tubules; however, the mechanism by which this occurs is not known. Because dopamine receptor subtypes can regulate and interact with each other, we studied the interaction of D3 and D1 receptors in rat renal proximal tubule (RPT) cells. The D3 agonist PD128907 increased the immunoreactive expression...

The competence of the duodenal 1ƒ¿, 25-(OH)2-D3 receptor system in embryonic chicks was studied in the reconstituted cytosol-chro matin system. The sucrose density gradient centrifugation following incubation of duodenal cytosol with 1x,25-dihydroxy-[3H]-vitamin D3 revealed that a cytosol 1x,25-dihydroxyvitamin D3 receptor existed in the duodenum of 18-day-old embryos. In the duodenum of 14-day...

Vitamin D3 is a promising preventative and therapeutic agent for prostate cancer, but its implementation is hampered by a lack of understanding about its mechanism of action. Upon treatment with 1a,25-dihydroxyvitamin D3 [1,25(OH)2D3, vitamin D3], the metabolically active form of vitamin D3, adult prostate progenitor/ stem cells (PrP/SC) undergo cell-cycle arrest, senescence, and differentiatio...

To clarify the effects of active vitamin D3 on pressor and vascular responses to vasoconstrictor substances, we studied pressor responses to the intravenous injection of norepinephrine or angiotensin II (Ang II) and vasoconstrictor responses to norepinephrine. Sprague-Dawley rats were given 1,25-dihydroxyvitamin D3 subcutaneously (200 ng/kg per day) for 14 days. The administration of 1,25-dihyd...

Vitamin D3 causes potent suppression of various cancer cells; however, significant supraphysiological concentrations of this compound are required for antineoplastic effects. Current combinatorial therapies with vitamin D3 are restricted to differentiation effects. It remains uncertain if autophagy is involved in vitamin D3 inhibition on leukemia cells. Here we show that besides triggering diff...

[(11)C]-(+)-PHNO is a D3 preferring PET radioligand which has recently opened the possibility of imaging D3 receptors in the human brain in vivo. This imaging tool allows characterisation of the distribution of D3 receptors in vivo and further investigation of their functional role. The specific [(11)C]-(+)-PHNO signal is a mixture of D3 and D2 components with the relative magnitude of each com...

BACKGROUND The three main vitamin D metabolizing enzymes, vitamin D3-25-hydroxylase (25-OHase, 25-hydroxylase), 25-hydroxyvitamin D3-1alpha-hydroxylase (1alpha-OHase, 1alpha-hydroxylase) and 25-hydroxyvitamin D3-24-hydroxylase (24-OHase, 24-hydroxylase), have been described in malignant breast tissue. This in vitro study aimed to obtain more information regarding the regulation of these enzymes...

Let us consider analogous problem for the metric space (X, d) with at least four points. Let A,B,C ∈ X be three fixed points. Then, for the point M ∈ X we suppose that a triangle can be formed from the distances d1 = d(M,A), d2 = d(M,B) and d3 = d(M,C) iff the following conjunction of inequalities is true: d1 + d2 − d3 ≥ 0 and d2 + d3 − d1 ≥ 0 and d3 + d1 − d2 ≥ 0. (1.1) If in conjunction (1.1)...