Central and peripheral receptors in guinea-pigs exposed to simulated high altitude.
Guinea-pigs, chronically exposed to simulated high altitude of 6000 m, showed alterations in some, but not all, neurotransmitter-receptor systems. Thus, peripheral (cardiac) beta-adrenergic receptors were decreased in numbers (Bmax) with an increased affinity although no alterations in endogenous cardiac norepinephrine content were found. In contrast, H1-histamine receptors in the guinea-pig ventricle and brain showed no changes in Bmax or affinity. Dopamine receptors of the caudate nucleus showed no differences between control and altitude-exposed guinea-pigs, although previous reports demonstrated a significant increase (19%) in the content of endogenous dopamine of the caudate. Thus, chronic exposure to simulated high altitude altered beta-adrenergic receptors so that they were more sensitive to small ligand concentrations and less sensitive to large ligand concentrations.
D000531:Altitude; D000818:Animals; D006168:Guinea Pigs; D006339:Heart Rate; D007700:Kinetics; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D011738:Pyrilamine / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D017983:Receptors, Catecholamine; D011954:Receptors, Dopamine / Q000378:metabolism; D011968:Receptors, Histamine / Q000378:metabolism*; D011969:Receptors, Histamine H1 / Q000378:metabolism*; D013134:Spiperone / Q000378:metabolism
D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D017983:Receptors, Catecholamine; D011954:Receptors, Dopamine; D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D013134:Spiperone; D011738:Pyrilamine; D009638:Norepinephrine