title: Hypoxia-induced changes in parasympathetic neurochemical markers in guinea pig heart.
abstract: Exposure of animals to hypoxia produces cardiovascular changes including right ventricular hypertrophy and alterations in heart rate. The activity of choline acetyltransferase, a neurochemical marker of parasympathetic innervation, and the density of muscarinic cholinergic receptors, measured by the binding of [3H]quinuclidinyl benzilate, were analyzed in the hearts of guinea pigs exposed to hypobaric hypoxia. We found a significant increase in the activity of choline acetyltransferase in the sinoatrial node in response to hypoxia after 7 or 14 days. In addition, we found significant decreases in the muscarinic receptor density in several contractile and conducting regions. The decrease in receptor density may reflect regulation by the level of occupancy; an increased occupancy may produce a decrease in muscarinic receptor number.
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001274:Atmospheric Pressure; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D006168:Guinea Pigs; D006321:Heart / Q000294:innervation; D006329:Heart Conduction System / Q000201:enzymology*; D000860:Hypoxia / Q000201:enzymology*; D009206:Myocardium / Q000201:enzymology*; D010275:Parasympathetic Nervous System / Q000201:enzymology; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D011950:Receptors, Cholinergic / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000378:metabolism*
chemical_list: D011950:Receptors, Cholinergic; D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate; D002795:Choline O-Acetyltransferase; D000109:Acetylcholine