Effects of oxytocin on angiotensin II-induced cardiac hypertrophy.

<p>Representative hematoxylin and eosin stained histological sections of the interventricular septal wall of the heart (original magnification x400) showing changes in cardiac myocyte size, left ventricular mass and heart to body weight ratio. Left ventricular mass index and heart weight were quantified at day 21 and 28 respectively following the infusion of saline (control), low dose oxytocin (LDOT), high dose oxytocin (HDOT), angiotensin II (AngII), a combination of angiotensin II and low dose oxytocin (AngII + LDOT) or angiotensin II and high dose oxytocin (AngII + HDOT). Data on bar graphs represent mean ± SEM (n = 6–8). Asterisks (*) indicate significant difference from the control group (* P<0.05, ** P<0.01).</p

Effects of oxytocin and angiotensin II on systolic and diastolic blood pressure.

<p>Systolic and diastolic blood pressure (mmHg) after 1, 7 and 28 days of subcutaneous infusion of saline (control), low dose oxytocin (LDOT), high dose oxytocin (HDOT), angiotensin II (AngII), a combination of angiotensin II and low dose oxytocin (AngII + LDOT) or angiotensin II and high dose oxytocin (AngII + HDOT). Data represent medians with interquartile range (n = 5–8). Asterisks (*) indicate significant difference from the control group on the same day (* P<0.05, ** P<0.01). Clear bars represent saline, low dose oxytocin (LDOT) or high dose oxytocin (HDOT) controls, and filled bars represent angiotensin II, or a combination of angiotensin II and low or high dose oxytocin.</p

Effects of oxytocin and angiotensin II on mean arterial pressure and heart rate.

<p>Mean arterial blood pressure (mmHg) and heart rate (beats/min) after 1, 7 and 28 days of subcutaneous infusion of saline (control), low dose oxytocin (LDOT), high dose oxytocin (HDOT), angiotensin II (AngII), a combination of angiotensin II and low dose oxytocin (AngII + LDOT) or angiotensin II and high dose oxytocin (AngII + HDOT). Data represent medians with interquartile range (n = 5–8). Asterisks (*) indicate significant difference from the control group on the same day (* P<0.05, ** P<0.01). Clear bars represent saline, low dose oxytocin (LDOT) or high dose oxytocin (HDOT) controls, and filled bars represent angiotensin II, or a combination of angiotensin II and low or high dose oxytocin.</p

Effects of oxytocin on angiotensin II-induced renal damage.

<p>Representative Masson’s trichrome stained histological sections of the renal cortex and medulla showing effects of oxytocin on angiotensin II induced renal damage. Pathological changes in the kidney were assessed by histological evaluation of glomerular necrosis, tubular degeneration, necrosis and epithelial sloughing and interstitial fibrosis (‡), and vascular congestion and extravasation (†). The original magnification was x100. Changes in renal function due to intra-renal damage were also evaluated as plasma urea to creatinine ratio and creatinine clearance. Measurements were made 28 days following the infusion of saline (control), low dose oxytocin (LDOT), high dose oxytocin (HDOT), angiotensin II (AngII), a combination of angiotensin II and low dose oxytocin (AngII + LDOT), or angiotensin II and high dose oxytocin (AngII + HDOT). Data represent the mean ± SEM (n = 6) and asterisks (*) on bar graphs indicate significant difference from the control group (* P<0.05, ** P<0.01).</p

Effects of oxytocin and angiotensin II on myocardial calcineurin activity.

<p>Activity of the myocardial calcium-dependent calcineurin phosphatase was quantified following the administration of saline (control), low dose oxytocin (LDOT), high dose oxytocin (HDOT), angiotensin II (AngII), a combination of angiotensin II and low dose oxytocin (AngII + LDOT) or angiotensin II and high dose oxytocin (AngII + HDOT) for 28 days. Data represent mean ± SEM (n = 5). Asterisks (*) indicate significant difference from the control group (* P<0.05, ** P<0.01).</p

Echocardiographic Evaluations of Left Ventricular Dimensions and Function.

<p>Data represent the mean ± SEM, n = 7–8 per group. Asterisks (*) and bold indicate significant difference compared with control (P < 0.05). LDOT, low dose oxytocin; HDOT, high dose oxytocin; AngII, angiotensin II; IVS_s, interventricular septum thickness during systole; IVS_d, interventricular septum thickness during diastole; LVID_s, left ventricular internal diameter during systole; LVID_d, left ventricular internal diameter during diastole; PW_s, left ventricle posterior wall thickness during systole; PW_d, left ventricle posterior wall thickness during diastole; FS, fractional shortening; EF, ejection fraction.</p><p>Echocardiographic Evaluations of Left Ventricular Dimensions and Function.</p

Effects of oxytocin and angiotensin II on plasma urea and creatinine concentrations, and plasma electrolytes and osmolality.

<p>Data represent mean ± SEM, n = 5–6 per group, asterisks (*) and bold indicate significant difference from control group (* P<0.05, ** P<0.01). LDOT, low dose oxytocin; HDOT, high dose oxytocin; AngII, angiotensin-II.</p><p>Effects of oxytocin and angiotensin II on plasma urea and creatinine concentrations, and plasma electrolytes and osmolality.</p

Effects of oxytocin and angiotensin II on plasma ANP and renin concentration.

<p>Plasma ANP and, prorenin and renin concentrations were quantified following the administration of saline (control), low dose oxytocin (LDOT), high dose oxytocin (HDOT), angiotensin II (AngII), a combination of angiotensin II and low dose oxytocin (AngII + LDOT) or angiotensin II and high dose oxytocin (AngII + HDOT) for 28 days. Data represent mean ± SEM (n = 5). Asterisks (*) indicate significant difference from the control group (* P<0.05, ** P<0.01).</p