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Angiotensin II Stimulates Sympathetic Neurotransmission to Adipose Tissue.

King VL, English VL, Bharadwaj K, Cassis LA - Physiol Rep (2013)

Bottom Line: These effects of AngII contribute to cardiovascular control.At doses that lowered body weight, AngII significantly increased ISBAT [(3)H]NIS binding density.AngII significantly increased the rate of NE decline in all tissues compared to saline.

View Article: PubMed Central - PubMed

Affiliation: Division of Cardiology, University of Kentucky, Lexington, KY 40536.

ABSTRACT
Angiotensin II (AngII) facilitates sympathetic neurotransmission by regulating norepinephrine (NE) synthesis, release and uptake. These effects of AngII contribute to cardiovascular control. Previous studies in our laboratory demonstrated that chronic AngII infusion decreased body weight of rats. We hypothesized that AngII facilitates sympathetic neurotransmission to adipose tissue and may thereby decrease body weight. The effect of chronic AngII infusion on the NE uptake transporter and NE turnover was examined in metabolic (interscapular brown adipose tissue, ISBAT; epididymal fat, EF) and cardiovascular tissues (left ventricle, LV; kidney) of rats. To examine the uptake transporter saturation isotherms were performed using [(3)H]nisoxetine (NIS). At doses that lowered body weight, AngII significantly increased ISBAT [(3)H]NIS binding density. To quantify NE turnover, alpha-methyl-para-tyrosine (AMPT) was injected in saline-infused, AngII-infused, or saline-infused rats that were pair-fed to food intake of AngII-infused rats. AngII significantly increased the rate of NE decline in all tissues compared to saline. The rate of NE decline in EF was increased to a similar extent by AngII and by pair-feeding. In rats administered AngII and propranolol, reductions in food and water intake and body weight were eliminated. These data support the hypothesis that AngII facilitates sympathetic neurotransmission to adipose tissue. Increased sympathetic neurotransmission to adipose tissue following AngII exposure is suggested to contribute to reductions in body weight.

No MeSH data available.


Related in: MedlinePlus

Chronic angiotensin II (AngII) infusion dose-dependently regulates body weight (A), food intake (B), and water intake (C). Baseline measurements of body weight, food and water intake were taken for 3 days prior to osmotic minipump implantation (arrow). Rats were administered either saline or AngII (200–600 ng/kg per minute) for 14 days by osmotic minipump. Measurements were taken daily at 10:00 am. Data are mean ± SEM from n = 8 rats/group; “*” denotes significantly different from saline.
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fig01: Chronic angiotensin II (AngII) infusion dose-dependently regulates body weight (A), food intake (B), and water intake (C). Baseline measurements of body weight, food and water intake were taken for 3 days prior to osmotic minipump implantation (arrow). Rats were administered either saline or AngII (200–600 ng/kg per minute) for 14 days by osmotic minipump. Measurements were taken daily at 10:00 am. Data are mean ± SEM from n = 8 rats/group; “*” denotes significantly different from saline.

Mentions: We performed dose–response studies infusing AngII (200–600 ng/kg per minute) or saline to rats for 14 days. At 200 ng/kg per minute of AngII, body weight was significantly decreased compared to saline on days 5–14 (Fig. 1A). At higher doses (400, 600 ng/kg per minute) of AngII, body weight was significantly decreased compared to saline on days 2–14 (Fig. 1A). Food intake was significantly decreased compared to saline at all doses of AngII on days 1–3 (Fig. 1B). In all rats infused with AngII, food intake gradually returned toward control in a dose- and time-dependent manner. However, body weight continued to decline. Reductions in food intake and body weight in response to 400 and 600 ng/kg per minute of AngII were significantly greater than those observed at 200 ng/kg per minute. The magnitude of the reduction in food intake and body weight was similar at doses of 400 and 600 ng/kg per minute of AngII, demonstrating that maximal responses had occurred. The weight of EF, but not LV was significantly reduced by infusion of AngII (Table 1; P < 0.05). Water intake was significantly increased by all doses of AngII (Fig. 1C; P < 0.05).


Angiotensin II Stimulates Sympathetic Neurotransmission to Adipose Tissue.

King VL, English VL, Bharadwaj K, Cassis LA - Physiol Rep (2013)

Chronic angiotensin II (AngII) infusion dose-dependently regulates body weight (A), food intake (B), and water intake (C). Baseline measurements of body weight, food and water intake were taken for 3 days prior to osmotic minipump implantation (arrow). Rats were administered either saline or AngII (200–600 ng/kg per minute) for 14 days by osmotic minipump. Measurements were taken daily at 10:00 am. Data are mean ± SEM from n = 8 rats/group; “*” denotes significantly different from saline.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3818081&req=5

fig01: Chronic angiotensin II (AngII) infusion dose-dependently regulates body weight (A), food intake (B), and water intake (C). Baseline measurements of body weight, food and water intake were taken for 3 days prior to osmotic minipump implantation (arrow). Rats were administered either saline or AngII (200–600 ng/kg per minute) for 14 days by osmotic minipump. Measurements were taken daily at 10:00 am. Data are mean ± SEM from n = 8 rats/group; “*” denotes significantly different from saline.
Mentions: We performed dose–response studies infusing AngII (200–600 ng/kg per minute) or saline to rats for 14 days. At 200 ng/kg per minute of AngII, body weight was significantly decreased compared to saline on days 5–14 (Fig. 1A). At higher doses (400, 600 ng/kg per minute) of AngII, body weight was significantly decreased compared to saline on days 2–14 (Fig. 1A). Food intake was significantly decreased compared to saline at all doses of AngII on days 1–3 (Fig. 1B). In all rats infused with AngII, food intake gradually returned toward control in a dose- and time-dependent manner. However, body weight continued to decline. Reductions in food intake and body weight in response to 400 and 600 ng/kg per minute of AngII were significantly greater than those observed at 200 ng/kg per minute. The magnitude of the reduction in food intake and body weight was similar at doses of 400 and 600 ng/kg per minute of AngII, demonstrating that maximal responses had occurred. The weight of EF, but not LV was significantly reduced by infusion of AngII (Table 1; P < 0.05). Water intake was significantly increased by all doses of AngII (Fig. 1C; P < 0.05).

Bottom Line: These effects of AngII contribute to cardiovascular control.At doses that lowered body weight, AngII significantly increased ISBAT [(3)H]NIS binding density.AngII significantly increased the rate of NE decline in all tissues compared to saline.

View Article: PubMed Central - PubMed

Affiliation: Division of Cardiology, University of Kentucky, Lexington, KY 40536.

ABSTRACT
Angiotensin II (AngII) facilitates sympathetic neurotransmission by regulating norepinephrine (NE) synthesis, release and uptake. These effects of AngII contribute to cardiovascular control. Previous studies in our laboratory demonstrated that chronic AngII infusion decreased body weight of rats. We hypothesized that AngII facilitates sympathetic neurotransmission to adipose tissue and may thereby decrease body weight. The effect of chronic AngII infusion on the NE uptake transporter and NE turnover was examined in metabolic (interscapular brown adipose tissue, ISBAT; epididymal fat, EF) and cardiovascular tissues (left ventricle, LV; kidney) of rats. To examine the uptake transporter saturation isotherms were performed using [(3)H]nisoxetine (NIS). At doses that lowered body weight, AngII significantly increased ISBAT [(3)H]NIS binding density. To quantify NE turnover, alpha-methyl-para-tyrosine (AMPT) was injected in saline-infused, AngII-infused, or saline-infused rats that were pair-fed to food intake of AngII-infused rats. AngII significantly increased the rate of NE decline in all tissues compared to saline. The rate of NE decline in EF was increased to a similar extent by AngII and by pair-feeding. In rats administered AngII and propranolol, reductions in food and water intake and body weight were eliminated. These data support the hypothesis that AngII facilitates sympathetic neurotransmission to adipose tissue. Increased sympathetic neurotransmission to adipose tissue following AngII exposure is suggested to contribute to reductions in body weight.

No MeSH data available.


Related in: MedlinePlus