Nonresonant powering of injectable nanoelectrodes enables wireless deep brain stimulation in freely moving mice.

Devices that electrically modulate the deep brain have enabled important breakthroughs in the management of neurological and psychiatric disorders. Such devices are typically centimeter-scale, requiring surgical implantation and wired-in powering, which increases the risk of hemorrhage, infection, and damage during daily activity. Using smaller, remotely powered materials could lead to less invasive neuromodulation. Here, we present injectable, magnetoelectric nanoelectrodes that wirelessly transmit electrical signals to the brain in response to an external magnetic field. This mechanism of modulation requires no genetic modification of neural tissue, allows animals to freely move during stimulation, and uses nonresonant carrier frequencies. Using these nanoelectrodes, we demonstrate neuronal modulation in vitro and in deep brain targets in vivo. We also show that local subthalamic modulation promotes modulation in other regions connected via basal ganglia circuitry, leading to behavioral changes in mice. Magnetoelectric materials present a versatile platform technology for less invasive, deep brain neuromodulation.

Antihypertensive, enzymatic, and hormonal activity of cilazapril, a new angiotensin-converting enzyme inhibitor in patients with mild to moderate essential hypertension.

The antihypertensive activity of cilazapril, a new nonsulfhydryl angiotensin-converting enzyme (ACE) inhibitor was evaluated in 20 outpatients (13 women, 7 men; mean age, 49 +/- 2.4 years) with mild to moderate essential hypertension, by means of an open dose-finding study of 10 weeks' duration. Cilazapril, 0.5 mg/day, was given, and the dose increased up to 10 mg/day if sitting diastolic blood pressure (SDBP) was not normalized (less than or equal to 90 mm Hg). Blood pressure measurements were carried out every 2 weeks before and 2 h after dosing. Predose and 2-h postdose measurements of plasma renin activity (PRA), angiotensin II (AII), plasma aldosterone (PA), and enzyme converting activity (ECA) were performed on the 1st day of active treatment and after 2 weeks of therapy. The SDBP decreased from 107.6 +/- 2 to 97.2 +/- 3 mm Hg 2 h after the initial dose (p less than 0.01). At the same time, ECA was inhibited 84.2 +/- 5% (p less than 0.01), AII decreased from 21.2 +/- 3 to 13.6 +/- 2 pg/ml (p less than 0.05), and PA from 208 +/- 29 to 119 +/- 14 pg/ml (p less than 0.01). After 2 weeks of therapy, ECA remained markedly reduced, by 68 +/- 6%, 24 h after the preceding cilazapril dose (p less than 0.01). The mean SDBP decreased from baseline to the end of treatment by 14.6 +/- 3 mm Hg (p less than 0.01). Cilazapril seems to be an effective antihypertensive drug which exerts potent and long-lasting ACE inhibition.

Natriuretic effect and changes in renal haemodynamics induced by enalapril in essential hypertension.

The purpose of this study was to evaluate the natriuretic effect and renal haemodynamic changes induced by enalapril in patients with essential hypertension. In a group of 11 patients with mild to moderate hypertension with normal renal function, and on a controlled sodium intake (80 mmol/day), a decrease in systolic and diastolic blood pressure was observed (p less than 0.001) after 16 weeks of enalapril treatment (20 mg/day), without a change in heart rate. An increase in plasma renin activity (p less than 0.05) without changes in serum aldosterone, and a decrease in exchangeable sodium (p less than 0.001) were present at the end of the treatment period. In 10 hypertensive patients also taking a dietary sodium of 80 mmol/day, the renal haemodynamics, humoral changes, and urinary sodium excretion were measured during 4 days of enalapril treatment (20 mg/day). There was an increase in urinary sodium excretion on the 3rd and 4th days of treatment (p less than 0.01). The effective renal plasma flow and fractional sodium excretion increased 72 hours after the beginning of treatment (p less than 0.01); the glomerular filtration rate did not change, and filtration fraction decreased at 72 hours. Mean blood pressure fell 2 hours after the first dose (p less than 0.01), and the maximum drop in intrarenal vascular resistance occurred after 72 hours of treatment (p less than 0.01). Plasma renin activity increased (p less than 0.05) and serum aldosterone decreased (p less than 0.01) 2 hours after the first dose. Thereafter, serum aldosterone increased progressively until it reached values similar to those with placebo at 48 and 72 hours of treatment. Urinary kallikrein fell during the 2nd and 3rd day of treatment (p less than 0.01). It was concluded that the decrease in exchangeable sodium was due to a natriuretic effect of enalapril. This effect presumably results from renal haemodynamic changes due to the reduction of angiotensin II. Other mechanisms, such as the reduction of aldosterone and accumulation of kinins, could be contributory factors.