Baroreceptor reflex dysfunction in the BACHD mouse model of Huntington’s disease.

Huntington's disease is a progressive, neurodegenerative disorder that presents with a triad of clinical symptoms, which include movement abnormalities, emotional disturbance and cognitive impairment. Recent studies reported dysfunction of the autonomic nervous system in Huntington's disease patients, which may contribute to the increased incidence of cardiovascular events in this patient population that often leads to death. We measured the baroreceptor reflex, a process dependent on proper autonomic function, in the BACHD mouse model of Huntington's disease. We found a blunted response of the baroreceptor reflex as well as significantly higher daytime blood pressure in BACHD mice compared to WT controls, which are both indications of autonomic dysfunction. BACHD mice had increased heart weight to tibia length ratios at 7 and 12 mo of age suggesting hypertrophic changes of the heart, which we speculate is a response to the increased blood pressure and aberrant baroreceptor reflex. Despite these structural changes, the hearts of BACHD mice continue to function normally as assessed by echocardiographic analysis. Studies of autonomic and cardiovascular function in BACHD mice may help elucidate the pathophysiology of Huntington's disease and aid in the development of clinical strategies to offset the incidence of fatal cardiovascular events in the Huntington's disease patient population. autonomic nervous system (ANS) that are detected even before the onset of other Huntington's disease symptoms. Misregulation of both the sympathetic and parasympathetic branches of the ANS have been described, whereby the sympathetic nervous system (SNS) becomes hyperactive in presymptomatic Huntington's disease patients while the activity of the parasympathetic nervous system (PNS) progressively declines [4][5][6] [7][8] [9] . These types of changes in the ANS are associated with poor prognosis for serious cardiovascular events that many times lead to death [10][11][12] . Further study of the cardiovascular system as well as autonomic activity in Huntington's disease patients may help in better understanding disease pathology that may lead to clinical strategies to help curb the number of cardiovascular events in the patient population.