No abstract

1. In anaesthetized, open-chest dogs, 2-nicotinamidoethyl nitrate (SG-75) administered intravenously (0.3-1 mg/kg) or intraduodenally (3 mg/kg) produced decrease in systemic blood pressure, coronary resistance, heart rate and an increase in coronary sinus outflow, but virtually no change in myocardial oxygen consumption and atrioventricular conduction. The effects of SG-75 administered intraduodenally emerged within a few minutes after dosing and lasted over about 1 h. 2. In isolated, blood-perfused sino-atrial node preparations of the dog SG-75 administered into the sinus node artery decreased slightly sinus rate at the dose which doubled blood flow through the artery. 3. In isolated, blood-perfused atrioventricular node preparations of the dog SG-75 administered into the atrioventricular node artery did not impair atrioventricular conduction even in doses which increased blood flow through the artery to more than twice the basal level. 4. In isolated, blood-perfused papillary muscle preparations of the dog SG-75 administered into the anterior septal artery scarely affected force of contraction of the papillary muscle at the dose which doubled blood flow through the artery, although in further large doses it produced a transient decrease in the force of contraction. In extremely large doses it produced ventricular fibrillation. 5. In anaesthetized, open-chest dogs in which cardiac input was kept constant SG-75 (0.01-1 mg/kg) administered into the ascending aorta increased venous return without changing systemic output. 6. 2-Nicotinamidoethyl alcohol, a denitrated compound of SG-75, had no vasodilator action in doses comparable to those of the parent compound. 7. These results indicate SG-75 to be a potential antianginal drug having no cardiodepressant actions but having properties uncharacteristic of the nitrates.

We have designed a new 4-week hospitalized phase II cardiac rehabilitation program. The purpose of the present study is to clarify whether the physical and psychological status of patients with myocardial infarction (MI) improves after participation in our program. Twenty-nine patients (27 males, two females) with acute MI who enrolled in the 4-week hospitalized phase II rehabilitation program were assessed. All patients enrolled in this study had received coronary interventions. The rehabilitation consisted of exercise training, education and counseling. We evaluated the physical and psychological status of the patients before and just after the program, and at a 6-month follow up. The physical status was assessed by exercise tolerance measured by the peak oxygen consumption and anaerobic threshold, frequency of exercise, and serum concentrations of triglyceride, total cholesterol, high-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol. The psychological status was assessed by the Spielberger state-trait anxiety inventory questionnaire (STAI) and the self-rating questionnaire for depression (SRQ-D). Thirty-four patients (27 men, seven women) with MI who did not participate in our rehabilitation program served as a control group. After participation in our rehabilitation program, exercise tolerance and the serum lipid profiles of the patients were improved compared with those before rehabilitation. These parameters had improved significantly 6 months after rehabilitation. The STAI anxiety score was improved significantly and the SRQ-D depression score tended to be improved just after the rehabilitation program. Regular physical activity was continued even 6 months after the completion of the program. Our hospitalized phase II cardiac rehabilitation program improved the management of cardiac risk factors and the psychological status in patients with MI. This comprehensive program may contribute to the secondary prevention of MI as well as the recovery of physical and psychological activities.

SUMMARY To assess the physiological role of atrial natriuretic factors in blood pressure regulation, we studied the effect of chronic infusion of a synthetic atrial natriuretic factor of 25 amino acid residues (Arg 102-Tyr 126) in rats with angiotensin H-induced hypertension. Rats were studied while on a normal sodium diet or during sodium loading with 1% NaCl solution used as drinking water. Systolic blood pressure decreased slightly during combined infusion of synthetic atrial natriuretic factor, 150 ju.g/kg/day, and angiotensin II, 900 /xg/kg/day. This effect was sustained for 3 days in rats receiving a regular sodium intake (p<0.01) and during sodium loading (p<0.01). Administration of synthetic atrial natriuretic factor to rats made hypertensive by a 3-day infusion of angiotensin II reduced blood pressure slightly, but not to control levels, and this effect was sustained for the remaining 3 days of the experiment in both dietary groups. These results indicate that a nonhypotensive dose of synthetic atrial natriuretic factor can modulate the vasopressor effect of angiotensin II. Thus, the attenuating effect may be involved in blood pressure regulation independently of sodium metabolism, although its actual physiological importance remains undetermined. (Hypertension 8: 748-753, 1986) KEY WORDS angiotensin II rat atrial natriuretic factor vascular smooth muscle blood pressure • sodium-water excretion A TRIAL natriuretic factor (ANF) is a potent na-/ \ triuretic and diuretic substance present in spe-X \~ cific granules of mammalian atrial cardiocytes.12 It can also relax isolated vascular smooth muscle and antagonize the vasoconstrictive actions of norepinephrine (NE) and angiotensin II (ANG II) in vitro.3 4 The natriuretic and vasorelaxant effects of ANF prompted us to investigate its possible role in the regulation of blood pressure, although its physiological relevance to blood pressure regulation has not been well documented.Since recent, extensive efforts have succeeded in purifying, sequencing, and synthesizing ANF, 5 " 9 more precise investigation of the vascular and renal actions of these peptides has become possible. Recently, by using ANF of 25 amino acid residues (Arg 102-Tyr 126) synthesized by Sugiyama et al. 10 and proven to have the same chemical characteristics and biological activities as natural ANF extracted from rat atrium and sequenced by Misono et al.,9 we demonstrated that a nonhypotensive dose of synthetic ANF inhibits the hypertension induced by chronic NE infusion in conscious rats."In the present study, we tried to evaluate the effect of chronic infusion of a synthetic ANF of 25 amino acid residues in conscious rats made hypertensive by chronic ANG II infusion. Materials and MethodsMale Sprague-Dawley rats (Charles River Japan, Atsagi, Japan) weighing 150 to 250 g were used. All rats were maintained in a room controlled for humidity and temperature. Throughout the study, each rat was housed in a metabolic cage designed to prevent fecesurine contact (Model ST; Sugiyamagen, Tokyo, J...