The antihypertensive effects of labetalol infusion (2 mg/min; maximal dose 150 mg) were evaluated in 22 subjects requiring rapid lowering of blood pressure because of severe hypertension, a hypertensive crisis after surgery, or before angiographic examination. Overall systolic and diastolic blood pressures were reduced from 201 ± 4 to 164 ± 4 mm Hg and from 123 ± 3 to 107 ± 3 mm Hg, respectively. By the end of the infusion, diastolic blood pressure in 16 (73%) subjects was lowered to ≤110 mm Hg. No adverse effects were encountered, but one subject had a transitory hypotensive episode that did not require treatment. Intravenous labetalol appears effective and well tolerated in the control of blood pressure in hypertensive emergencies. Clinical Pharmacology and Therapeutics (1985) 37, 615–618; doi:

No abstract

Congestive heart failure was produced in nine dogs following surgical removal of the tricuspid valve. Six dogs developed ascites with or without peripheral edema, and four dogs remained ascites-free for 5, 6, and 11 weeks (one dog in this latter group did later develop ascites 14 weeks following operation; it was therefore studied twice and included in both groups). Systolic aortic pressure, sodium balance, right atrial pressure, glomerular filtration rate, sodium para-aminohippurate clearance, plasma aldosterone, norepinephrine, renin activity, and antidiuretic hormone levels were measured in each dog before surgery and during the experimental period of the steady state of edema in the dogs of group A, and at 5, 6, and 11 weeks in the four dogs of group B. Right atrial pressure increased considerably and glomerular filtration rate and sodium para-aminohippurate clearance decreased markedly in each dog. The most significant and important findings were (1) normal sodium balance in the dogs of group B without ascites, whereas four of the six dogs with ascites had a markedly positive sodium balance; (2) increased antidiuretic hormone activity levels in all dogs with congestive heart failure and ascites in contrast with the absence of any change in the dogs without ascites. The changes in plasma aldosterone, norepinephrine, and renin activity levels were not consistent. It is suggested that the antidiuretic hormone may play a role in the formation of ascites and edema in dogs with congestive heart failure following total removal of the tricuspid valve.

1970. Renin activity and norepinephrine, cation, rind water contents sf cardiovascular tissue of dogs with congestive heart failure and ascites. Can. J. Physiol. Pharnaacol. 48, 463468. Six dogs with congestive heart failure and ascites were studied for ( a ) renin, norepinephrine, water, sodium, potassium, calcium. and lrnagnesium contents in cardiovascular tissues; ( h ) plasma renin activity and renin substrate; ( c ) renal renin activity, juxtaglomerular index, and glucose-6-phosphate dehydrogenase activity in macula densa cells, and a-glycero-6-phosphate dehydrogenase activity in inacula densa cells and juxtaglonaerular bodies. The most important findings were: (a) a cignificant decrease in renal renin activity and in the juxtaglomcrular index coinciding with increased activities of glucose-6-phosphate and a-glycero-6-phosphate dehydrogenases in nnacula dens2 cells when compared with normal renal hissue: ( b ) a highly significant increase in norepinephrine content in branches of mesenteric veins combined with a decrease in norepinephrine content in most arteries studied; ( c ) a significant increase in the sodium content of most arteries studied, without any change h water content.