Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study we evaluated the effects of placebo or acute bromocriptine (BC) administration (2.5 mg orally) on plasma catecholamines, systolic and diastolic blood pressure (BP), heart rate, and plasma PRL in six normal subjects [group I, mean age 33.2 +/- 5.4 (SD) yr] in the supine as well as upright position. BC induced a significant decrease in plasma norepinephrine in the supine [167.7 +/- 16.8 (SEM) vs. 101.9 +/- 33.7 pg/ml, P less than 0.005] and upright positions [397.3 +/- 27.7 vs. 211.3 +/- 26.7 pg/ml, P less than 0.005], a decrease in systolic and diastolic BP and a decrease in plasma PRL (P less than 0.01). After standing, epinephrine levels increased significantly (53.6 +/- 11.8 vs. 226.4 +/- 71.0 pg/ml, P less than 0.05). The study was repeated in a second group of seven normal subjects (mean age, 32.3 +/- 12.9 yr) after placebo or metoclopramide (20 mg orally) plus BC. In this group metoclopramide, a central and peripheral antidopaminergic agent, counteracted the BC-induced effects found in group I, both in the basal and stimulated conditions. Plasma PRL increased significantly (P less than 0.025). Finally, to assess the effect of peripheral dopaminergic blockade on BC-induced changes in sympathetic outflow, we repeated the study in seven normal subjects (group III, mean age, 30.1 +/- 5.0 yr) after placebo or domperidone (20 mg orally) plus BC. Domperidone blocked the effects of BC on norepinephrine and BP in the supine position. On standing there was a significant decrease in systolic (P less than 0.05) and diastolic (P less than 0.05) BP and an increase in epinephrine levels (58.9 +/- 12.2 vs. 109.8 +/- 24.6 pg/ml, P less than 0.05) was still observed. Plasma PRL increased significantly (P less than 0.025). The results of this study suggest that the inhibition of sympathetic outflow induced by BC is peripherally mediated. As peripheral dopamine receptor blockade did not counteract all the effects after BC during standing, dopaminergic modulation of central reflex sympathetic activation is suggested.
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PMID:Effects of different dopaminergic antagonists on bromocriptine-induced inhibition of norepinephrine release. 672 27

The aim of the present study was to determine the effect of prolonged administration of the dopamine antagonist domperidone on follicular development, ovulation and endocrine profiles in anoestrous mares. Anoestrous mares (n=16) were maintained under natural photoperiod and ambient temperature. Eight of the mares were treated with domperidone each day from 15 January until the first ovulation of the year. The mean number and size of follicles > or =20 mm in diameter were significantly greater in domperidone-treated mares than in control mares by day 14 of treatment. The day of first ovulation was significantly earlier in domperidone-treated mares than in control mares (mean +/- SEM: 51 +/- 8.2 and 129 +/- 13.6 days, respectively; P < 0.01). The eight domperidone-treated mares all ovulated during treatment and the mean interval from the start of treatment to the day of first ovulation was 27 days (range 15-55 days). Six of the eight domperidone-treated mares underwent normal cycles after the first ovulation, whereas there was a prolonged interval (mean = 67 days) before the second ovulation in the other two mares. Domperidone administration resulted in significantly higher plasma prolactin concentrations measured at 0, 4, 8, 12 and 24 h on day 7 of treatment compared with untreated controls (25.5 +/- 15.8 versus 2.5 +/- 3.0 ng ml(-1)). The concentrations of LH and oestrogen conjugates were significantly higher in domperidone-treated mares compared with control mares by day 28 of treatment. There were no differences in FSH concentrations in domperidone-treated and control mares. The significant increases in follicular development and concentrations of oestrogen conjugates that were observed to occur without concurrent increases in FSH concentration indicate that either domperidone or prolactin may have a direct effect on the ovary.
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PMID:Influence of the dopamine antagonist domperidone on the vernal transition in seasonally anoestrous mares. 2068 Nov 30