Haemodynamic Changes Associatedc with Obesity and High Blood Pressure in Crats with Ventromedial Hypothalamic Lesions

Reisin, Efrain; Suárez, Daniel; Fröhlich, Edward D.

doi:10.1042/cs059397s

Cited by 8 publications

(8 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bernardis and Skelton 26 showed that although VMH lesions prevented the usual increase in tail-cuff systolic pressure occurring in 27-day-old rats, similar lesions made at later ages were ineffective. Mean carotid pressures recorded by Reisin et al 10 were 10 mm Hg higher in VMH-lesioned than in sham-operated (with averages of 128±3 and 118±3 mm Hg, respectively) rats anesthetized with pentobarbital, but then Reisin and Wilson, 11 using either tail-cuff or intra-arterial measurements, were later unable to find any significant differences between lesioned and sham-operated rats. Hence, the existence of hypertension in rats with obesity induced either genetically or by VMH destruction remains unresolved.…”

Section: Baroreceptor Reflex Alterations Produced By Cholinergic B-amentioning

confidence: 89%

See 1 more Smart Citation

Baroreceptor reflex impairment and mild hypertension in rats with dietary-induced obesity.

1990

View full text Add to dashboard Cite

Cardiovascular dysfunction associated with obesity was assessed by comparing rats that had been maintained on a regular or high fat diet since weaning. Rats on the high fat diet not only gained weight faster than age-matched controls but also had higher systolic and mean pressures. Development of mild hypertension in obese rats was first detected by indirect tail-cuff measurement and confirmed later by recording intra-arterial pressures directly from indwelling femoral catheters. To assess baroreceptor reflex sensitivity, reflex heart rate responses were elicited by lowering blood pressure with sodium nitroprusside or elevating it with phenylephrine. Initial tests showed that, although reflex tachycardia during depressor responses to sodium nitroprusside did not differ between groups, reflex bradycardia during pressor responses to phenylephrine was weaker in obese than in control rats. Underlying autonomic mechanisms were then examined by repetition of baroreceptor reflex tests after cholinergic blockade with methylatropine or /3-adrenergic blockade with propranolol. Reflex tachycardia was equally inhibited in both groups by either antagonist. By contrast, reflex bradycardia was reduced more in obese than in control rats by /3-adrenergic blockade but was equally reduced by cholinergic blockade. Because residual responses after /3-adrenergic blockade would represent remaining parasympathetic mediation, these results indicate that reflex bradycardia was selectively impaired because of deficient parasympathetic mediation. Considered collectively, our results suggest that impaired parasympathetic mediation of reflex bradycardia could either result from or contribute to the blood pressure elevation in obese rats. ) in which obesity is induced by programming pups to overeat immediately after birth and then maintaining them on a high fat diet. Inasmuch as this model is derived by overfeeding rather than by genetic or neurosurgical manipulation, it probably mimics the natural development of obesity more closely. Accordingly, we aimed to determine cardiovascular status in obese and control rats nurtured as described by Oscai. From 4 to 10 months of age, blood pressures and heart rates were monitored by tail-cuff measurement and, on finding that obese rats had become mildly hypertensive, terminal experiments were done to compare reflex heart rate responses

show abstract

Section: Baroreceptor Reflex Alterations Produced By Cholinergic B-amentioning

confidence: 89%

“…Reflex chronotropic responses were analyzed by plotting heart rate changes against changes in blood pressure. For each infusion, eight points for heart rate corresponding with mean pressure changes of 5,10,15,20,25,30,35, and 40 mm Hg were thereby compiled.…”

Section: Drugs Data Processing and Statisticsmentioning

confidence: 99%

Baroreceptor reflex impairment and mild hypertension in rats with dietary-induced obesity.

1990

View full text Add to dashboard Cite

show abstract

“…More recent ly, hemodynamic analyses of rats with VMH-induced obesity indicated that these animals were mildly hypertensive [19]. The average mean arterial pressure of obese rats has been observed as 128 mm Hg, as com pared to 118 mm Hg for lean control animals [19] . Heart rates are similar between lean and obese rats.…”

Section: Ventromedial Hypothalamic Lesion-induced Obesitymentioning

confidence: 99%

“…While important similarities between VMH lesion-induced obesity and some as pects of clinical obesity and hypertension are established [19,20], as with other models reviewed at this point, little cardiac function data is available. Also, as with the other models, blood pressure of obese, hyperten sive rats is only mildly or moderately ele vated.…”

Section: Ventromedial Hypothalamic Lesion-induced Obesitymentioning

confidence: 99%