Inhibition of serotonin synthesis within the medulla and posterior hypothalamus by cardiac vagal afferents during acute myocardial ischemia in the rat.
Serotonin synthesis, as estimated by the accumulation of 5-hydroxytryptophan 25 min following aromatic-L-amino acid decarboxylase inhibition, was measured in the medulla, pons-midbrain and posterior and anterior hypothalamus of rats subjected to left coronary artery ligation and their sham-operated controls. Left coronary artery ligation led to reduction in the rate of serotonin synthesis in the medulla and posterior hypothalamus. The topical administration of lidocaine to the left ventricle or vagotomy completely obviated these occlusion-induced changes. We conclude that there is an inhibition of serotonergic activity in the medulla and posterior hypothalamus after left coronary artery occlusion in the rat. The afferent signal arises from receptors in the ischemic left ventricle and is conducted by the vagus.
D000344:Afferent Pathways / Q000503:physiopathology; D000818:Animals; D003327:Coronary Disease / Q000503:physiopathology*; D004195:Disease Models, Animal; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000096:biosynthesis*; D014628:Vagotomy; D014630:Vagus Nerve / Q000503:physiopathology*
D012701:Serotonin; D008012:Lidocaine