Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of oxytocin, administered intracerebroventricularly in doses of 1, 10, 100 and 1000 pmol, were studied on the disappearance of catecholamines induced by alpha-methyl-p-tyrosine in microdissected nuclei of the rat brain. Oxytocin dose-dependently decreased the utilization of noradrenaline in the lateral and medial septal nuclei and anterior hypothalamic area, whereas an enhanced utilization was observed in the nucleus supraopticus. Tendency towards a change in utilization of noradrenaline was found in the dorsal septal nucleus and the lateral amygdala. Utilization of dopamine was not significantly affected in any of the nuclei of the brain studied. Tendency towards a decrease in utilization of dopamine was observed in the nucleus caudatus, globus pallidus and medial septal nucleus. It thus appears that oxytocin elicited changes in only a restricted number of brain nuclei. Interestingly, these nuclei contain cell bodies (nucleus supraopticus) and terminals (other nuclei) of the oxytocin system in the brain. Though the effects of oxytocin were not as widespread as those previously seen after administration of vasopressin, it is worthy of note that, in general, the effects of oxytocin were opposite to those seen after vasopressin. The opposite effects of vasopressin and oxytocin on catecholamine metabolism could be related to the opposite effects of the two peptides on behaviour, neuroendocrine and autonomic regulation.
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PMID:Oxytocin affects utilization of noradrenaline in distinct limbic-forebrain regions of the rat brain. 652 41

Infusions of Phyllanthus sellowianus or P. niruri (Euphorbiaceae) are a popular remedy in Brazil for kidney and bladder stones. This study describes the isolation of an alkaloid from P. sellowianus, denoted ALK-1, and compares its antipasmodic activity with that of papaverine on isolated strips of guinea pig ileum and rat uterus, and rat aorta rings. ALK-1 and papaverine promoted a dose-dependent flattening of the dose-response curves obtained to acetylcholine and histamine on ileum strips and of the dose-response curves to acetylcholine and oxytocin on uterine strips. A non-competitive antagonism of noradrenaline-induced contractions by the P. sellowianus alkaloid was also demonstrated on aortic rings. Whereas the antispasmodic potency (pD'2 values) of papaverine did not depend on the muscle preparation and agonist used, ALK-1 exhibited a greater potency on the ileum strips than on the uterine or aortic preparations. Because of this selective antispasmodic action on the ileum, ALK-1 was equipotent to papaverine on this tissue, but was about 10-fold less potent than papaverine on uterine smooth-muscle. The dose-response curves to CaCl2 obtained for potassium-depolarized uterine strips were shifted to the right by both antispasmodics. Similar pA2 values with slopes not differing from unity -1.0 were obtained from Schild plots of the data, suggesting that competitive antagonism of calcium entry into the cell is a mechanism of action common to both alkaloids. The presence of at least one potent antispasmodic alkaloid in P. sellowianus justifies the popular use of infusions of this plant. Smooth muscle relaxation within the urinary or biliary tract probably facilitates the expulsion of kidney or bladder calculi.
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PMID:Antispasmodic effects of an alkaloid extracted from Phyllanthus sellowianus: a comparative study with papaverine. 652 14

The effects of exogenous noradrenaline on the milk-ejection response were determined for nine Holstein cows. Noradrenaline was injected (0.95 nmol/kg) 15 s after the start of teat stimulation (preparation) or infused (0.13 nmol/kg per min, after bolus injection of 0.47 nmol/kg) starting 10 min before milking for 20 min. Cows were prepared (udder wash and dry) for 1 min before milking. Both injection and infusion resulted in approximately a 3.5-fold increase in peripheral noradrenaline at 1.75 min after the start of milking (baseline noradrenaline 0.83 and 0.89 nmol/l plasma; at 4 min, 2.00 and 3.00 nmol/l). Prolactin release was delayed and oxytocin release enhanced, while milk yield was decreased by 8.6% for both treatments. The maximum rate of milk flow was also depressed by treatment. In contrast, milking time increased for injection and decreased for infusion. In addition, a milk-yield-dependent change in the pattern of milk flow was seen in response to treatment. In medium-yield animals, two distinct milk-flow peaks were apparent and injection delayed the time to the second peak. We conclude that physiologically meaningful increases in peripheral noradrenaline can inhibit milk-ejection response by means of a peripheral mechanism not involving inhibition of release of oxytocin.
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PMID:Small increases in peripheral noradrenaline inhibit the milk-ejection response by means of a peripheral mechanism. 669 36

A highly sensitive and specific radioimmunoassay for LRF was applied to the measurement of endogenous LRF in various hypothalamic extracts. Specific antiserum was obtained by injecting LRF conjugated to human serum albumin with glutaraldehyde. Thyrotropin-releasing hormone, lysine vasopressin, oxytocin, noradrenaline, LH, FSH and cortical extracts did not appear to affect the assay, and the maximum cross-reaction observed with the LRF analogs tested was 8.5 p. 100 with LRF 2-10. The best detection limit (0.4 pg/tube) was usually obtained when the labelled LRF had been purified by polyacrylamide gel electrophoresis. Within and between-assay coefficients of variation were 8.0 and 12.6 p. 100, respectively (from B/Bo = 20 to 80 p. 100). Synthetic LRF administered to rams by intravenous injection was readily detectable in the peripheral plasma. However, the direct measurement of plasma endogenous LRF may give misleading results due to non-specific interference by plasma factors. No endogenous LRF could be detected in plasma methanol or acetone extracts obtained from rats and rams in various physiological conditions. The inhibition curves parallel to the synthetic LRF curve were obtained by diluting the crude hypothalamic extracts of rams and rats, and a good correlation (r = 0.997) with the Ramirez-McCann bioassay resulted, indicating that using radioimmunoassay to determine hypothalamic LRF content may be fruitful in studying hypothalamo-pituitary gonad interactions. The LRF content of rat and ovine hypothalami ranged from 2-8 to 20-80 ng of LRF, respectively.
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PMID:Reassessment of LRF radioimmunoassay in the plasma and hypothalamic extracts of rats and rams. 676 Feb 82

The general pharmacology of aclacinomycin A, a new antitumor antibiotic, was studied in mice, rats, guinea-pigs, frogs, rabbits and dogs. The LD50 values of aclacinomycin A were 32.5 mg/kg (i.v.), 30.1 mg/kg (i.p.), 33.9 mg/kg (s.c.) and 69.7 mg/kg (p.o.), respectively in male mice, and 28.8 mg/kg (i.v.), 21.1 mg/kg (i.p.), 26.4 mg/kg (s.c.) and 58.6 mg/kg (p.o.), respectively in male rats. Aclacinomycin A had no effect on the central nervous system except potenciation of the pentobarbital sodium-induced anesthesia in mice. The contraction of isolated heart was stimulated in frogs while slightly inhibited in rabbits at higher concentration. Transient increases in the heart rate and the blood flow of peripheral vasculature were observed but the blood pressure was slightly lowered with respiratory excitation in anesthetized rabbits and dogs. The ECG (II-lead) demonstrated slight depression of R wave amplitude and slight sinus arrhythmia in dogs. Aclacinomycin A inhibited the contraction of isolated smooth muscle and antagonized some spasmogens. It inhibited the spontaneous movement of isolated rabbit ileum and rat uterus at higher concentration, and antagonized acetylcholine, histamine, serotonin and barium chloride in the contraction of isolated guinea-pig ileum. The antagonism was competitive to oxytocin and noncompetitive to acetylcholine in rat uterus, and noncompetitive to noradrenaline in rat deferent duct. The drug showed no apparent effect on the gastrointestinal propulsion in mice and on mucous membrane of the stomach in rats. However, it depressed gastric acid secretion in rats while slightly increased bile secretion in guinea-pigs. Urine volume and urinary excretion of electrolytes (Na+, K+) decreased in rats. Vascular permeability was slightly inhibited by the drug in rabbits and mice. No hemolytic effect was shown. Aclacinomycin A showed no antigenicity in anaphylactic reaction and SCHULTZ-DALE reaction in guinea-pigs.
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PMID:[General pharmacology of aclacinomycin A (author's transl)]. 692 61

Antihypertensive and general pharmacological properties of 1-[2-(1,3-dimethyl-2-butenylidene)hydrazino]phthalazine (budralazine) were studied in comparison with those of hydralazine. Single oral administration of budralazine (4--15 mg/kg) to DOCA/saline hypertensive rats resulted in a dose-related and sustained antihypertensive effect which was 2--3 times less potent than that of hydralazine. However, there were no remarkable differences between both drugs in the hypotensive magnitude after the 4-week treatment of spontaneously hypertensive rats (SHR) with their higher doses. After single oral administration, budralazine was about 8 times less potent than hydralazine in increasing plasma renin activity in normotensive rats. At effective antihypertensive doses, budralazine inhibited spontaneous motor activity (mice), gastrointestinal propulsion (mice), gastric emptying rate (rats), gastric secretion (rats), urine output and urinary electrolyte excretion (rats) as well as carrageenan-induced paw edema formation (rats), which were essentially less potent than those produced by hydralazine. Budralazine at 6 mg/kg i.v. exhibited a slowing of neocortical EEG (cats) and a slight increase in spinal monosynaptic potentials (cats) and inhibited gastrointestinal motility (dogs). The same dose of hydralazine produced an increase in occurrence of the neocortical fast waves, an inhibition of the monosynaptic potentials and the carotid sinus reflex (dogs) and a stimulation of intestinal motility followed by prolonged and marked reduction. Budralazine (10(-5) g/ml) slightly potentiated contractile response of isolated guinea-pig vas deferens to noradrenaline, whereas hydralazine (10(-4) g/ml) inhibited the response. Budralazine (10(-5) g/ml), like hydralazine (10(-4) g/ml), produced a nonspecific antagonism against the contractile response of isolated guinea-pig ileum to various spasmogens, and both drugs (10(-4) g/ml) reduced either spontaneous motility or oxytocin-induced motility in isolated rat uterus.
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PMID:Antihypertensive and general pharmacological properties of budralazine. 702 95

Hormonal responses to breastfeeding were studied during the 1st 3 postpartum weeks in 10 women smoking more than 15 cigarettes/day and in 10 nonsmoking controls. All had had uncomplicated pregnancies resulting in term deliveries of infants weighing above 2800 gm. Mean age, parity, and infant birthweights were 26.5 years, 2, and 3390 gm in smokers and 28 years, 2, and 3615 gm in nonsmokers. The only significant clinical difference was earlier weaning in smokers. Mean serum prolactin (PRL) was consistently lower in smokers. Basal levels differed significantly on the 1st day and in repetitive samples on the 21st postpartum days, when the difference was significant prior to and 120 minutes after breastfeeding. The difference after 12 hours of abstinence from smoking was also significant. Increments in serum PRL during breastfeeding were not significantly different between smokers and nonsmokers, and not influenced by abstinence from smoking. Basal levels and sucking-induced increments of oxytocin-linked neurophysin (hNp2) were similar in smokers and nonsmokers and were not influenced by abstinence from smoking. At the 3rd week, mean basal vasopressin-linked neurophysin (hNpl) was .31 ng/ml in nonsmokers and .40 ng/ml and .37 ng/ml respectively in smokers abstaining and not abstaining. Neither smoking nor breastfeeding induced any significant alteration in serum hNpl. Serum nicotine and plasma adrenaline but not dopamine or noradrenaline increased significantly during smoking. Basal levels of catecolamines were not significantly altered after abstinence from smoking. The lower basal PRL levels of heavy smokers may shorten the period of lactation.
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PMID:Suppressed prolactin but normal neurophysin levels in cigarette smoking breast-feeding women. 713 67

Alkaloid B reversibly blocked the responses of rat diaphragm to electrically induced stimulations via the phrenic nerve. The alkaloid had no effect on the responses of the diaphragm elicited by direct electrical stimulation. The responses of frog rectus abdominis muscle to acetylcholine were inhibited by alkaloid B. Alkaloid B reversibly antagonised the responses of rabbit duodenum to exogenously applied acetylcholine. The contractile effect of oxytocin on rat uterus was specifically inhibited by alkaloid B. The effects of alkaloid B on isolated muscle preparations were concentration-dependent. However, the effect of dopamine and noradrenaline on rat vas deferens was not altered by alkaloid B.
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PMID:Pharmacological effects of Synclisia scabrida alkaloid B on some isolated muscle preparations. 715 94

The different reactions caused by 4 drugs (terbutaline sulphate, noradrenaline, PGF2 alpha and oxytocin) and Ca on the longitudinal and circular muscles of a pregnant rat myometrium as well as their electrical activity and the degree of their co-ordinated contractions during pregnancy were studied in vitro. The results were as follows; 1. The circular muscle showed plateau potential in the middle, but spike potential became dominant in the late stage. The longitudinal muscle, however, showed spike potential throughout. 2. Well co-ordinated contraction between 1) the neighboring longitudinal muscles, 2) the neighboring circular muscles, and 3) the longitudinal and circular muscles were evident in the late stage. 3. The circular muscle was stimulated by noradrenaline in the middle stage, but inhibited by it in the late stage, whereas the longitudinal muscle was inhibited throughout. 4. The circular muscle developed high sensitivity to terbutaline sulphate in the late stage, whereas the longitudinal muscle showed constant sensitivity throughout. 5. PGF2 alpha failed to cause contracture of the circular muscle in the late stage. 6. The high resistance of the circular muscle to low Ca in the middle stage weakened in the late stage, whereas the longitudinal muscle resistance was low in both stages. In conclusion, in the final stage of pregnancy, the action of the circular muscles resembles that of the longitudinal ones, however, the contracture of the circular muscles is difficult to notice. For the purpose of the expulsion of the uterine contents, the longitudinal muscle may play main role. While the longitudinal muscle is in the contracture state, the circular muscle may show repeated coordinated contractions, thereby assisting the expulsion of the contents.
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PMID:[Changes of the contraction of the circular and longitudinal muscles of pregnant rat myometrium during pregnancy (author's transl)]. 724 Aug 31

1 The effects of vasopressin on the membrane and contractile properties of smooth muscle cells of guinea-pig mesenteric arteries, and mesenteric and portal veins were investigated in various ionic environments by means of a micro-electrode technique and an isometric tension recording method. The results were compared with those obtained with oxytocin and noradrenaline (NA).2 In the mesenteric jejunal artery, the mean membrane potential was -56.6 +/- 2.3 mV, s.d, and the membrane was electrically quiescent. Application of outward current pulses generated small graded responses, and the current voltage relationship was linear with application of an inward current pulse.3 Vasopressin and NA depolarized the membrane and increased the membrane resistance. Vasopressin was a 1000 times more potent than oxytocin in depolarizing the membrane. In high concentrations, vasopressin (1 x 10(-3) or 1 x 10(-2) iu/ml) or NA (5.9 x 10(-5) M) generated slow oscillatory membrane potential changes (slow waves) and spikes during the depolarization. The excitatory actions of vasopressin and NA were not suppressed by tetrodotoxin (3.1 x 10(-7) M) or ouabain (1.3 x 10(-6) M) and the actions of vasopressin were not suppressed by adrenoceptor blocking agents (3.9 x 10(-7) M phentolamine or 3.6 x 10(-7) M propranolol).4 The depolarization induced by vasopressin or NA is mainly due to a decrease in the K-permeability of the membrane. However, the contribution of other ionic species to the depolarization induced by vasopressin or NA differed, e.g. in low concentrations of [Na](o), the NA-induced depolarization was suppressed to a greater extent than that due to vasopressin. In low concentrations of [Ca](o), the vasopressin-induced depolarization was suppressed to a greater extent than with NA.5 In low concentrations of [Ca](o) and in the presence of vasopressin or NA, spike generation was inhibited but slow waves were not. In low concentrations of [Na](o), the vasopressin-induced slow waves and spikes were for the great part preserved, but with a high concentration of [Ca](o), vasopressing-induced slow waves were suppressed.6 Both vasopressin and NA produced contractions in the jejunal mesenteric artery. However, the maximum contraction in response to vasopressin was larger than that to NA, although both induced similar membrane depolarization. In a low concentration of [Na](o), vasopressin but not NA produced a contraction.7 In the cranial mesenteric artery, NA (5.9 x 10(-5) M) depolarized the membrane and produced a contraction, while vasopressin (1 x 10(-1) iu/ml) and oxytocin (1 x 10(-1) iu/ml) neither depolarized the member nor produced a contraction. In the mesenteric vein, NA (5.9 x 10(-5) M) slightly depolarized the membrane and produced a small contraction. On the other hand, in the portal vein, NA (5.9 x 10(-7) M) produced a marked depolarization and a contraction. Vasopressin (1 x 10(-1) iu/ml) and oxytocin (1 x 10(-1) iu/ml) produced neither excitatory nor inhibitory actions in these veins.8 It is concluded that vasopressin acts on only small muscular arteries, while NA acts on all mesenteric vessels, particularly the portal vein. Therefore, the hepatic portal vascular resistance may be increased by NA and reduced by vasopressin.
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PMID:Effects of vasopressin on smooth muscle cells of guinea-pig mesenteric vessels. 728 85


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