Bradycardia following injection of 6-hydroxydopamine into the intermediate portion of nucleus tractus solitarius medialis.
Studies were carried out to determine the effects of selective destruction of the catecholamine innervation of the intermediate portion of the nucleus tractus solitarius medialis (NTSm) on mean arterial pressure and heart rate in conscious rats. Following bilateral injections of 6-hydroxydopamine into the intermediate portion of NTSm, animals demonstrated a prolonged bradycardia, but no changes in mean arterial pressure or mean arterial pressure lability, when compared with controls. Results indicate that the baroreceptor reflex loop which mediates bradycardia is sensitive to impulses from catecholamine axons entering the intermediate NTSm.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D006892:Hydroxydopamines / Q000494:pharmacology*; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects*; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000187:drug effects; D051381:Rats; D011950:Receptors, Cholinergic / Q000187:drug effects
D006892:Hydroxydopamines; D011950:Receptors, Cholinergic