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Nitric oxide modulates myocardial substrate uptake during pregnancy.
Author(s) -
Williams Jeffrey G,
Recchia Fabio A,
Hintze Thomas H
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1229
Subject(s) - glucose uptake , nitric oxide , chemistry , substrate (aquarium) , medicine , vasodilation , pharmacology , endocrinology , biology , ecology , insulin
The aim of this study was to determine the role of NO in the control of myocardial substrate uptake during pregnancy (P) in the dog. An increase in NO production, a decrease in peripheral vascular resistance and an increase in cardiac output characterize normal P. During P, MAP decreased from 105±4 to 97±3, LNAME increased MAP to 111±4 mmHg. dP/dtmax increased from 3108±85 to 3381±92 during P and decreased to 2819±78 mmHg/s with LNAME. HR increased from 90±4 to 110±5 during P and LNAME produced a bradycardia (70±9 beats/min). The coronary vasodilation induced by activation of the Bezold‐Jarisch (BJ) reflex is NO dependent. Coronary blood flow (CBF) increased by BJ from 0.71±0.04 to 1.07±0.03 ml/min/g, during P CBF increased from 0.85±0.03 to 1.45±0.07. LNAME abolished the increase in CBF. We have proposed previously that NO has a modulatory action on substrate uptake. We examined the uptake of glucose, lactate and free fatty acids (FFA) during P. FFA uptake (mEq/min) increased from 14±2 to 32±2 during P while NOS inhibition decreased uptake to 8±2. Glucose uptake did not change during P (0±3 mg/min), LNAME increased uptake to 6.6±3. Lactate uptake did not change during P (11±3 umol/min) however LNAME increased uptake to 21±4. During P there is an increase in NO which supports an increase in FFA uptake while maintaining glucose and lactate uptake at low levels despite the increase in cardiac work. (Supported by HL50142 and PO‐43023)