總結(jié) |
Adenosine is an endogenous nucleoside generated locally in tissues under conditions of hypoxia, ischemia, or inflammation. It modulates a variety of physiological functions in many tissues including brain and heart.1,2It exerts its action via four specific adenosine receptors (also named P1 purinergic receptors): A1-Adenosine Receptor (A1AR), A2A-Adenosine Receptor (A2AAR), A2B-Adenosine Receptor (A2BAR), and A3-Adenosine Receptor (A3AR). All are integral membrane proteins and members of the G Protein-Coupled Receptor superfamily. They share a common structure of seven putative transmembrane domains, an extracellular amino terminus, a cytoplasmic carboxyl terminus, and a third intracellular loop that is important in binding G proteins.1-3 The various adenosine receptors can be distinguished on the basis of their differential selectivity for adenosine analogs.1-3A1AR is widely distributed and has been well characterized. High expression of A1AR is found in brain (mainly in the cortex, cerebellum, and hippocampus), dorsal horn of the spinal cord, adrenal gland, and atria, and to a lower extent in several other tissues including adipose tissue, colon, and kidney.2,4A1AR modulates the activity of several ion channels. Activation of A1AR (by adenosine, its major agonist) inhibits N-type Ca2+ channels via a voltage-dependent, pertussis toxin (PTX)-sensitive pathway in neurons of the rat major pelvic ganglia (MPG).5Since A1AR is the most prominent adenosine receptor in adipocytes, it has become a natural target for research on obesity, which is a major health problem.6,7 A possible role in cell proliferation and carcinogenesis has also been suggested for A1AR.8-10
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Western blot analysis of rat brain (lanes 1,3) and rat kidney (lanes 2,4) lysates:
1,2. Anti-A1 Adenosine Receptor antibody ( AMM05522G), (1:200).
3,4. Anti-A1 Adenosine Receptor antibody, preincubated with the control peptide antigen.
Expression of A1 Adenosine Receptor in rat cortex
Immunohistochemical staining of rat cortex frozen section using Anti-A1 Adenosine Receptor antibody ( AMM05522G). A. A1 Adenosine Receptor (green) appears in neurons (triangles) and in astrocytes (arrows). B. Parvalbumin staining (red) appears in cortical interneurons. C. Confocal merge of images demonstrates the existence of A1 Adenosine Receptor in a subset of cortical interneurons and astrocytes.
Expression of A1 Adenosine Receptor in rat medial septum
Immunohistochemical staining of rat medial septum frozen section using Anti-A1 Adenosine Receptor antibody ( AMM05522G). A. A1 Adenosine Receptor (green) appears in neurons (right pointing triangles). B. Parvalbumin staining (red) appears in medial septal neurons. C. Confocal merge of demonstrates expression of A1 Adenosine Receptor in a subset of medial septal neurons.
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