Subtle Cardiovascular Dysfunction in the Unilateral 6-Hydroxydopamine-Lesioned Rat

Abstract

The present study evaluated whether the unilateral 6-hydroxydopamine (6-OHDA) model of Parkinson's disease produces autonomic deficits. Autonomic parameters were assessed by implanting a small radiofrequency telemetry device which measured heart rate variability (HRV), diurnal rhythms of heart rate (HR), core body temperature (cBT) and locomotor activity (LA). Rats then received 6-OHDA lesion or sham surgery. 6-OHDA lesioned rats exhibited head and body axis biases, defective sensorimotor function (“disengage” test), and prominent apomorphine rotation (all P < .05 versus controls). Diurnal rhythm of HR was lower for 6-OHDA lesioned rats (n = 8) versus controls (n = 6; P < .05). Whilst HR decreased similarly in both groups during the day, there was a greater decrease in HR for the 6-OHDA lesioned rats at night (by 38 b.p.m. relative to 17 b.p.m. for controls). LA and cBT did not differ between surgery groups. This study indicates the unilateral 6-OHDA model of PD shows subtle signs of cardiovascular autonomic dysfunction.

Stress-induced dopamine release in human medial prefrontal cortex-18F-Fallypride/PET study in healthy volunteers

“…To our knowledge, the involvement of the mesolimbic and mesocortical DA system in autonomic responses in humans has not been the subject of intense scrutiny. Yet, in experimental animals, dopaminergic neurons in the ventral tegmental area have been shown to regulate HR Synapse (Deschamps and Couture, 2005;Sakata et al, 2002;Slack et al, 2010). Interestingly, central DA deficiency is observed in pure autonomic failure in humans (Goldstein et al, 2008).…”

Nonuniform Cardiac Denervation Observed by 11C-meta-Hydroxyephedrine PET in 6-OHDA-Treated Monkeys

“…Nonuniform cardiac innervation, affects cardiac repolarization and has been associated with arrhythmias [6] , [15] . Future preclinical experiments using telemetric measurements of heart rate, blood pressure, and locomotive activity [50] , [51] will allow their identification in awake animals. Injections of vasoactive pharmaceuticals such as phenylephrine or sodium nitroprusside may also help characterize the cardiovascular response.…”

Propolis as a Potential Disease-Modifying Strategy in Parkinson’s disease: Cardioprotective and Neuroprotective Effects in the 6-OHDA Rat Model

“…In addition to impaired voluntary movements, 6-OHDA-injured rats exhibit a variety of nonmotor disturbances [ 17 ]. Some studies have shown that 6-OHDA-treated rats have lower patterns of HR and HRV than their control counterparts [ 18 , 19 , 20 ]. Knowledge of the pathological dysfunctions in an animal model is critical for recognizing prospective therapeutic targets as adjunctive therapies aimed at multiple levels of pathology are required in PD.…”