Mlg. Correia et al., Leptin acts in the central nervous system to produce dose-dependent changes in arterial pressure, HYPERTENSIO, 37(3), 2001, pp. 936-942
Citations number
25
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Systemic leptin increases energy expenditure through sympathetic mechanisms
, decreases appetite, and increases arterial pressure. We tested the hypoth
esis that the presser action of leptin is mediated by the central nervous s
ystem. The interaction of dietary salt with leptin was also studied. Leptin
was infused for 2 to 4 weeks into the third cerebral ventricle of Sprague-
Dawley rats. Arterial pressure was measured by radiotelemetry. To control f
or the effects of leptin on body weight, vehicle-treated rats were pair-fed
to the leptin group. Intracerebroventricular infusion of leptin at 200 ng/
h in salt-depleted rats caused a reduction in food intake, weight loss, tac
hycardia, and decreased arterial pressure. Leptin at 1000 ng/h caused furth
er reduction in food intake, weight loss, and tachycardia and prevented the
hypotensive effect of weight loss observed in pair-fed, vehicle-treated an
imals. Intracerebroventricular leptin at 1000 ng/h in high-salt-fed rats al
so caused a sustained presser response (+3+/-1 mm Hg), but high-salt intake
did not potentiate the presser effect of leptin. Intracerebroventricular l
eptin potentiated the presser effect of air-jet stress. Intravenous adminis
tration of the same dose of leptin (1000 ng/h) did not change weight or art
erial pressure, suggesting a direct central nervous system action. In contr
ast, a high dose of intravenous leptin (18 000 ng/h) caused weight loss and
prevented the depressor effect of weight loss. In conclusion, this study d
emonstrates that high-dose leptin increases arterial pressure and heart rat
e through central neural mechanisms but leptin does not enhance salt sensit
ivity of arterial pressure. Leptin appears to oppose the depressor effect o
f weight loss.