Influence of vitamin B6 Deficiency on L-Aromatic Amino Acid Decarboxylase in the Organs of Spontaneously Hypertensive Rats (SHR) II. Long Term Feeding

1975 ◽  
Vol 12 (5) ◽  
pp. 311-314
Author(s):  
Noboru Yoshimine ◽  
Fumio Kuzuya
Keyword(s):  
Amino Acid ◽  
Vitamin B6 ◽  
Spontaneously Hypertensive Rats ◽  
Acid Decarboxylase ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Amino Acid Decarboxylase ◽  
Aromatic Amino Acid Decarboxylase ◽  
Vitamin B6 Deficiency

Enhancement of the Anti-Hypertensive Effect of Methyldopa and other Anti-Hypertensive Drugs by Carbidopa in Spontaneously Hypertensive Rats

1976 ◽  
Vol 51 (s3) ◽  
pp. 407s-410s
Author(s):  
A. Scriabine ◽  
C. T. Ludden ◽  
C. A. Stone ◽  
R. J. Wurtman ◽  
C. J. Watkins
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Specific Radioactivity ◽  
Acid Decarboxylase ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Amino Acid Decarboxylase ◽  
Aromatic Amino Acid Decarboxylase ◽  
Nervous System Activity ◽  
Biochemical Studies ◽  
Tyrosine Content

1. A peripheral inhibitor of l-aromatic amino acid decarboxylase, carbidopa [(—)-l-α-hydrazino-3,4-dihydroxy-α-methylbenzenepropanoic acid monohydrate], at doses up to 25 mg/kg intraperitoneally or 30 mg/kg orally had no effect on directly recorded arterial pressure of spontaneously hypertensive rats derived from the Wistar/Okamoto strain. It enhanced, however, the anti-hypertensive effects of methyldopa, hydrallazine, guanethidine and clonidine, and, to a lesser extent, reserpine and hydrochlorothiazide. The mechanism of this enhancement is presently unknown, but biochemical studies support the assumption that carbidopa is likely to reduce sympathetic nervous system activity. 2. The conversion of [3H]tyrosine (given intraperitoneally) to dopa (3,4-dihydroxyphenylalanine) and catecholamines was measured in the hearts and adrenals of control rats and animals pretreated with carbidopa (100 mg/kg, intraperitoneally). Carbidopa significantly decreased the accumulation of 3H-labelled catecholamines in both organs and increased their total tyrosine content and the specific radioactivity of tyrosine.

Antihypertensive Activity of Metyrosine in Spontaneously Hypertensive Rats and its Enhancement by Carbidopa

1978 ◽  
Vol 55 (s4) ◽  
pp. 255s-257s ◽  
Author(s):  
A. Scriabine ◽  
C. T. Ludden ◽  
C. S. Sweet ◽  
C. C. Porter ◽  
E. H. Ulm ◽  
...  
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Antihypertensive Activity ◽  
Acid Decarboxylase ◽  
Maximal Effect ◽  
Hypertensive Rats ◽  
Duration Of Action ◽  
Spontaneously Hypertensive ◽  
Amino Acid Decarboxylase ◽  
Low Concentrations ◽  
Noradrenaline Synthesis

1. Metyrosine (l-α-methyl-p-tyrosine, Demser), an inhibitor of tyrosine hydroxylase, has moderate antihypertensive activity in spontaneously hypertensive rats (20–40 mmHg fall in mean arterial pressure) at 20–80 mg/kg intraperitoneally or 80 mg/kg orally. The maximal effect is reached at 4 h after treatment and the duration of action exceeds 12 h. 2. A peripheral inhibitor of amino acid decarboxylase, carbidopa ([—]-l-α-hydrazino-3,4-dihydroxy-α-methylbenzenepropanoic acid monohydrate), (25 mg/kg intraperitoneally) has little or no antihypertensive activity alone but if administered 5 min before metyrosine, it greatly enhances the antihypertensive potency of metyrosine. The relative potency of metyrosine + carbidopa (both intraperitoneally), as compared with metyrosine alone, was 74 with 95% confidence limits of 31 and 142. 3. In another series of experiments, the antihypertensive activity of metyrosine (80 mg/kg orally) was enhanced and prolonged by carbidopa, (25 mg/kg intraperitoneally). This effect was independent of the interval between administration of the two drugs (5 or 45 min). 4. Metyrosine (20 mg/kg intraperitoneally), reduced brain and heart noradrenaline concentrations in spontaneously hypertensive rats as determined 6 h after treatment. Carbidopa (25 mg/kg intraperitoneally) slightly enhanced the noradrenaline-depleting effect of metyrosine in the whole brain but not in the heart. 5. After metyrosine or carbidopa + metyrosine, low concentrations of α-methyldopamine were found in the brain of spontaneously hypertensive rats. Methyldopa at the same dose (20 mg/kg intraperitoneally) produced a 10 times greater increase in α-methyldopamine concentrations. 6. The inhibition by carbidopa of noradrenaline synthesis in sympathetic nerve endings in the heart and in peripheral blood vessels may be at least partially responsible for the carbidopa-induced enhancement of the antihypertensive action of metyrosine.

Long-term administration of prazosin improves bladder storage function: Results from a study in spontaneously hypertensive rats

2011 ◽  
Vol 18 (11) ◽  
pp. 785-791 ◽  
Author(s):  
Nobuhiro Haga ◽  
Ken Aikawa ◽  
Kei Ishibashi ◽  
Tomohiko Yanagida ◽  
Masanori Nomiya ◽  
...  
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Storage Function ◽  
Term Administration
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