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The Effects of Short‐Term Immobilization Stress on Muscarinic Receptors, β‐Adrenoceptors, and Adenylyl Cyclase in Different Heart Regions
Author(s) -
MYSLIVEČEK JAROMÍR,
ŘÍČNÝ JAN,
PALKOVITS MIKLÓS,
KVETŇANSKÝ RICHARD
Publication year - 2004
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1296.038
Subject(s) - muscarinic acetylcholine receptor , adenylyl cyclase , receptor , medicine , endocrinology , chemistry , adrenergic receptor , biology
A bstract : Heart muscarinic receptors (MR) and β‐adrenoceptors (BAR) belong to a large family of G‐protein‐coupled receptors. Although the role of catecholamines in the stress has been under keen investigation for many years, the effects of immobilization on this pair of receptors, considering their almost completely opposite actions in the heart, are not yet known. We have studied the effects of short‐term immobilization (for 120 min) with different times of decapitation after the end of the immobilization period (0, 3, and 24 h) on MR, BAR (β 1 ‐AR and β 2 ‐AR using radioligand binding studies), and adenylyl cyclase (AC; using high‐pressure liquid chromatography detection of cAMP) in different heart regions (left and right atria with or without cardiac ganglion cells [auriculae], septum, and left and right ventricles). The effects of one immobilization period were first apparent after 24 h. Stress brought about a downregulation of MR and BAR with decrease in AC activity. These effects were regionally specific and were predominantly expressed in the right atria, which is rich in ganglia cells, and in the right ventricles. Our results indicate that stressful stimuli can influence not only BAR, but MR, and that AC activity can also be affected. This finding is in good agreement with our previous hypothesis that parallel changes are possible in the number of this pair of receptors on cell membranes.