G.M. Lew

Circadian rhythms in blood pressure and norepinephrine in genetically hypertensive and normotensive rats.

Abstract 1. 1. Circadian changes in systolic blood pressure (B.P.) were determined in genetically hypertensive (GH) and normotensive rats and correlated with changes in norepinephrine (NE) levels in various brain regions, the heart and the adrenal glands. 2. 2. In the hypothalamus of GH rats a relatively low level of NE was found when the B.P. reached a peak level during the late dark phase, and a relatively high level of this catecholamine was found when the B.P. was low in the light period. 3. 3. The most significant difference between hypertensive and control rats in NE concentration in the brainstem and heart was found in the early light hours, when the B.P. was relatively low.

Changes in blood pressure and norepinephrine concentration following administration of estrogens to genetically hypertensive and normotensive rats

Abstract 1. Changes in systolic blood pressure and NE concentration were found in genetically hypertensive (GH) and normotensive rats following administration of diethylstilbestrol (DES) and mestranol. 2. Increases in the weights of the adrenal glands of GH and normotensive rats and of the hearts of normotensive rats only following administration of DES were found. 3. A decrease in adrenal NE concentration in GH rats following DES treatment and an increase in cardiac NE in normotensive rats following treatment with mestranol were found.

Effects of mestranol on blood pressure and norepinephrine in young normotensive and genetically hypertensive rats.

Abstract 1. Increases in blood pressure (B.P.) were found in 3-month-old normotensive and genetically hypertensive (GH) rats following administration of mestranol. 2. In normotensive rats a depletion in hypothalamic and adrenal NE accompanied the increase in B.P. which was found at the end of 3 weeks of drug treatment. 3. In GH rats, after an experimental period of 3 weeks, a decrease in cardiac NE occurred, while at the end of 6 weeks, a depletion in adrenal NE which was accompanied by the increase in B.P., was found.

Microtubular tau protein after cocaine in cultured SH-SY5Y human neuroblastoma

1. SH-SY5Y, a human neuroblastoma cell line, was used as a tissue culture model to examine the hypothesis that cocaine may affect the metabolism of tau protein which stabilizes microtubules and promotes microtubule assembly. 2. Cocaine hydrochloride (10(-9)-10(-3) M) caused dose-dependent reductions in cell number, with 10(-3) M causing 28% reduction after 48 hr. 3. This drug also decreased tau protein (50 Kd) in the cytoplasmic (supernatant) as well as the membrane (pellet) fraction after 48-hr treatment.

Circadian changes in norepinephrine turnover in rats following administration of estrogen.

Abstract 1. Circadian changes in norepinephrine (NE) turnover were found in 4-month-old rats following administration of estrogen. 2. In the hypothalamus NE turnover occurred in the late-dark period only in mestranol-treated rats. 3. At the late-dark and early-light phases NE turnover was found to occur in the cerebellum of control rats, but was not found in mestranol-treated rats at these times nor in the mid-light period. 4. Following estrogen treatment adrenal NE turnover was discovered at early- and mid-light phases. 5. Cardiac NE turnover was not found to occur in mestranol-treated rats at any of the three times sampled.

Changes in microtubule-associated tau protein in human neuroblastoma cells after phencyclidine.

1. A human neuroblastoma cell line, SH-SY5Y, was used to study the effects of phencyclidine (PCP) on microtubule-associated tau protein, which acts in vivo chiefly to induce the assembly of tubulin and in vitro to promote microtubule polymerization. 2. PCP (1.0 mM) decreased tau protein (50 kD) in the cytoplasmic (supernatant) fraction as well as in the membrane (pellet) fraction. 3. These changes in tau protein were accompanied by decreases of 30-95% in cell number after concentrations of PCP, 0.25-1.0 mM, respectively. 4. After 0.5 mM PCP cytoplasmic and membrane fractions of SH-SY5Y cells showed 100 and 84% increases in total protein, respectively.

Age and dosage differences in response of genetically hypertensive and normotensive rats to estrogen treatment.

Abstract 1. Normotensive rats (6 months old) showed a 4% increase in blood pressure (B.P.) after low doses of estrogen, with no decreases in norepinephrine (NE) levels as were found previously in younger rats. 2. Genetically hypertensive (GH) rats (6 months old) treated with low or high doses of estrogen showed no significant increases in B.P. nor changes in NE levels. 3. GH rats (3 months old) showed a greater response to high doses of estrogen as seen in greater increases in B.P. and changes in hypothalamic and adrenal NE content.

Developmental changes in catecholamines in organs and brain regions of genetically hypertensive rats

Abstract 1. Developmental changes in catecholamine concentrations were determined in genetically hypertensive (GH) and normotensive rats. 2. Changes in catecholamine concentrations and organ weights differed in relation to age, organ and brain region. 3. Norepinephrine (NE) and epinephrine (E) contents of adrenal glands were greater in 11- and 16-week-old GH rats than in corresponding controls, the difference in adrenal NE concentration being greater in the younger animals ( P 4. A significant decrease ( P

Tau protein after delta-9-tetrahydrocannabinol in a human neuroblastoma cell line

1. A human neuroblastoma cell line, SH-SY5Y, was used to determine the effects of delta-9-tetrahydrocannabinol (THC) on microtubule-associated tau protein. 2. After 48-hr treatment, THC (10(-9) M) decreased 50 kD tau protein in the cytoplasmic (supernatant) fraction, and in the membrane (pellet) fraction the drug (10(-7) M) also decreased 50 kD tau protein. 3. This reduction in tau protein was accompanied by a 27% reduction (P < 0.05) in the membrane (pellet) total protein after (10(-7) M) THC and a 28% increase (P < 0.02) in cytoplasmic (supernatant) total protein after 10(-9) M THC.

Age differences in blood pressure and norepinephrine concentration in normotensive rats after higher doses of estrogen.

1. Normotensive rats (3 months old) showed 6-9% increases in blood pressure (B.P.) after high doses of estrogen, with increases in hypothalamic and adrenal norepinephrine (NE). 2. Older normotensive rats (6 months old) showed 4-11% increases in B.P. after high doses of estrogen with a decrease in brainstem NE.