ERNAU 25 Interference with Excitation by 5-Benzoyloxy-2-Iminohexahydropyrimidine Hydrochloride. M. Y. SPIEGELSTEIN AND C. Y. KAO 34 Negative Chronotropic Effects of McN A-343 and Nicotine in Isolated Guinea-Pig Atria: Insensitivity to Blockade by Tetrodotoxin. ACHILLES J. PAPPANO AND ROBERT A. REMBISH 40 Ganglionic Stimulation: Mechanism of the Positive Inotropic and Chronotropic Effects of Ang...

Several studies have focused on the beneficial effects of peripheral angiotensin-(1-7) [Ang-(1-7)] in the regulation of cardiovascular function, showing its counterregulatory effect against the actions of angiotensin II (ANG II). However, its actions in the central nervous system are not completely understood. In the present study, we investigated the intracellular mechanisms underlying the act...

Background—The definition of a normal heart rate (HR) response to exercise stress testing in women is poorly understood, given that most studies describing a normative response were predominately based on male data. Measures of an attenuated HR response (chronotropic incompetence) and age-predicted HR have not been validated in asymptomatic women. We investigated the association between HR resp...

background : envenomation by hemiscorpius lepturus is not painful and the clinical manifestations include bloody urine due to hemoglobinuria or hematuria, dermonecrotic reactions,cardiac arrhythmia and in minority of cases acute renal failure which may lead to death following disseminated intravascular coagulation in infants. cardiac effects of envenomation by h. lepturus venom including inotro...

Release of atrial natriuretic factor (ANF) following an elevation in heart rate is thought to be mediated primarily by a change in atrial stretch. To evaluate the direct effect of chronotropic stimulation on ANF release, isolated rat left atria were electrically paced (1-9 Hz) at constant resting tension (0.5-4 g), and the amount of immunoreactive ANF (IRANF) released at each frequency and tens...

Gastric peristaltic contractions are driven by electrical slow waves modulated by neural and humoral inputs. Excitatory neural input comes primarily from cholinergic motor neurons, but ACh causes depolarization and chronotropic effects that might disrupt the normal proximal-to-distal spread of gastric slow waves. We used intracellular electrical recording techniques to study cholinergic respons...

The effects of phenylephrine and methoxamine were studied on pacemaker activity in the sinoatrial node and on atrial and ventricular contractility in isolated, blood-perfused atrial and ventricular preparations of dogs. Each drug was administered directly into the cannulated sinus node artery of an isolated atrium or the anterior descending branch of the isolated left ventricle over a period of...

OBJECTIVES Recently, we showed that some new synthetic compounds structurally related to cilostamide (4-(1,2-dihydro-2-oxoquinolin-6-hydroxy)- N-cyclohexyl-N-methylbutanamide), a selective phosphodiesterase 3 (PDE3) inhibitor, produce inotropic effect comparable to that of IBMX (3-isobutyl-1-methylxanthine), a non-selective PDE inhibitor, but with differential chronotropic effect. In this inves...