摘要:

SUMMARY1. Serum prolactin levels were measured in large cohorts of schizophrenic patients (67 males and 42 females) and normal subjects (78 males and 42 females).2. There was no significant differences between the serum prolactin levels of patients and controls, except in the age group 15–29 years. There were no significant differences between the serum prolactin levels of males and females, either among the patients or the control subjects.3. The rise in serum prolactin levels after the commencement of neuroleptic medication in the patients was greater in females than in males even though the female patients received neuroleptics at lower doses.4. These data indicate that serum prolactin levels in unmedicated males and females are similar; however, the prolactin response to neuroleptic medication is greater in females than in male

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00511.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. The control of extracellular fluid volume (ECFV) in normal pregnancy may be related to changes in atrial natriuretic peptide. Previous studies in non‐pregnant subjects have suggested that plasma atrial natriuretic peptide (ANP) increases in response to dietary sodium supplementation because of an increase in plasma volume, although this has not been measured directly.2. Nine women who were pregnant in the third trimester undertook oral sodium supplementation (136 mmol) for 5 days in addition to their usual diet. Twenty‐four hour urinary sodium excretion increased by 125 ± 54 mmol/day (mean ±s.d.;P<0.01). Plasma volume was unchanged, although total ECFV tended to increase (P<0.09 and bodyweight increased (1.3 ± 1.4 kg;P<0.01) at the end of these diets.3. Plasma ANP increased by 30.7 [8.6, 34.5] pmol/L (median [25th, 75th percentile];P<0.05), while plasma renin concentration decreased significantly from 7.3 [6.2, 11.2] to 2.6 [1.7, 3.9]pmol angiotensin I/mL (P<0.01), as did plasma aldosterone concentration (1435 [1162,1722] to 753 [595, [110]fmol/mL;P<0.01). Plasma vasoactive intestinal peptide was unchanged.4. Pregnant women respond to increased dietary sodium with an increase in plasma ANP in the absence of a significant increase in plasma volume. The acute regulation of plasma ANP in response to increases in dietary sodium in pregnant women does not appear to be mediated by changes in intravascular fluid

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00512.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. The present study investigated thein vitroeffect of dopamine on platelet responses in healthy subjects.2. Dopamine concentrations over 5 μmol/L induced a primary aggregating response and a slight release of α‐granule proteins, β‐thromboglobulin and platelet factor‐4 in all subjects. In 25% of investigated subjects a delayed secondary aggregation was observed with dopamine concentrations over 100 μmol/L.3. Low dopamine concentrations (5–7.5 nmol/L) increased the platelet sensitivity to other aggregating agents (adenosine diphosphate, collagen and sodium arachidonate). The effect of subaggregating concentrations of serotonin was potentiated by dopamine.4. The effect of dopamine on platelet responses was prevented by low concentrations of α‐adrenoceptor antagonists (phentolamine and yohimbine); antagonists of dopamine receptors (haloperidol and domperidone) were able to decrease the extent of the dopamine‐induced secondary aggregating wave in the responders, but they failed to prevent the primary aggregation and the effects on platelet response to other aggregating agents.5. The present data demonstrated that the effects of dopamine on human platelets are mainly mediated by interactions with

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00513.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. The vascular endothelium produces endothelium‐derived relaxing factor (EDRF) or nitric oxide (NO), which exerts vasodilation through cyclic guanosine monophosphate (cGMP) as a second messenger. To determine whether EDRF has any vasodilating and natriuretic action in man, the present study examined the effects ofl‐arginine (l‐Arg), a substrate for NO, on the responses of mean blood pressure (MBP) and heart rate (HR); plasma concentrations of cGMP, atrial natriuretic factor (ANF) and nitrite/nitrate (NOx); urinary excretion of sodium, cGMP and NOx; and urinary flow in eight normal male subjects. These parameters were compared with those following saline infusion in the same subjects. Clearance of para‐aminohippuric acid (PAH) and inulin was studied in five normal subjects.2. Infusion ofl‐Arg (30 g) caused a significant fall in MBP (–8 mmHg) with a concomitant rise in HR (10 beats/min), while saline infusion had no effects on these parameters.3. Neitherl‐Arg nor saline infusion caused appreciable changes in plasma concentrations of ANF or NOx. Plasma cGMP concentrations increased significantly during (1.7‐fold) and after (1.9‐fold)l‐Arg infusion, but only slightly (1.3‐fold) during saline infusion.4. Urine flow increased more remarkably followingl‐Arg infusion than that following saline infusion. Remarkable increases in urinary excretion of sodium and fractional excretion of sodium were observed afterl‐Arg infusion compared with those after saline infusion. Natriuresis was associated with enhanced urinary excretion of cGMP and Nox. Urinary NOx excretion showed positive correlations with urinary flow (r= 0.69,P<0.001) and with urinary cGMP excretion (r= 0.60,P<0.01). PAH clearance showed significant increase byl‐Arg infusion, while no significant change of inulin clearance was observed.5. These date suggest that infusion ofl‐Arg causes hypotension and diuresis/natriuresis associated with increase in renal plasma flow, possibly via the format

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00514.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. Airways derived from different levels of the lung exhibit a difference in the reactivity and sensitivity to agonists. We have evaluated the effect of acetylcholine and cholinergic selective (pirenzepine, gallamine and 4‐dipherylacetoxymethyl piperidine [4‐DAMP]) and non‐selective (atropine) antagonists on bovine proximal and distal smooth muscle preparations.2. The distal preparations are more sensitive to acetylcholine than proximal bronchi. The relaxant effect of three selective antagonists on the distal and proximal tissues was the same when the results for each drug were compared.3. Atropine and 4‐DAMP were more potent than pirenzepine and gallamine in relaxing both proximal and distal bovine smooth muscle preparations.4. These data suggest that the muscarinic sites on the smooth muscle of bovine airways are of the M3

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00515.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. This study investigated the effects of tacrine (l,2,3,4‐tetrahydro‐9‐aminoacridine) on the resting and stimulation‐induced (SI) release of radioactive substances from isolated preparations of rat atria and rabbit pulmonary artery in which the noradrenergic transmitter stores had been labelled with [3H]‐noradrenaline, and from rat atrial preparations in which cholinergic transmitter stores had been labelled with [3H]‐acetylcholine. In addition, the effect of tacrine on the uptake of [3H]‐noradrenaline by noradrenergic nerves in rat atria was determined.2. Tacrine produced concentration‐dependent increases in the resting efflux of radioactivity from both the [3H]‐noradrenaline‐loaded artery and atrial preparations. Blockade of neuronal amine transport with desipramine reduced the release of radioactivity evoked by tacrine from atria but not that evoked from artery preparations. Inhibition of monoamine oxidase by pargyline pretreatment markedly reduced the tacrine‐evoked release of radioactivity in both atrial and artery preparations.3. The radioactivity released from [3H]‐noradrenaline‐labelled rat atrial preparations by 30 μmol/L tacrine consisted entirely of the deaminated metabolite [3H]‐DOPEG. The evoked release of [3H]‐DOPEG from atria was reduced by approximately 50% by desipramine (1 μmol/L). When atrial monoamine oxidase had been inhibited by pargyline treatmentin vivoandin vitro, 30 μmol/L tacrine evoked the release of [3H]‐noradrenaline instead of [3H]‐DOPEG. However, the amounts of [3H]‐noradrenaline released by tacrine when monoamine oxidase was inhibited were only about 25% of the amounts of [3H]‐DOPEG released in untreated atria.4. Tacrine, in concentrations of 1 and 10 μmol/L, enhanced the release of radioactivity evoked by field stimulation of [3H]‐noradrenaline‐loaded rabbit pulmonary artery preparations. This effect was unaltered by desipramine or pretreatment with pargyline. However, in artery preparations pretreated with pargyline, a high concentration of tacrine (100 μmol/L) markedly reduced SI efflux. In contrast to the findings with artery preparations, tacrine (1–30 μmol/L) did not alter SI efflux in rat atrial preparations.5. It is concluded that tacrine displaces noradrenaline from intraneuronal transmitter stores of sympathetically‐innervated tissues, and that the displaced amine is totally metabolized by monoamine oxidase before leaving the nerve terminals. When deamination of neuronal cytoplasmic noradrenaline is prevented, only a portion of the noradrenaline displaced from storage vesicles passes to the extracellular space. It is likely that the transfer of cytoplasmic noradrenaline out of the terminals is limited by the activity of the amine transport mechanism.6. Tacrine, in concentrations of 30 and 100 μmol/L, reduced the uptake radioactivity by rat atria incubated for 5 min periods in [3H]‐noradrenaline to approximately 83 and 26%, respectively, of control uptake. Desipramine was much more potent than tacrine in inhibiting [3H]‐noradrenaline uptake: 1 μmol/L desipramine reduced the uptake radioactivity to approximately 18% of the control.7. Tacrine (30 μmol/L) did not alter the resting efflux of radioactivity from [3H]‐acetylcholine‐labelled rat atrial preparations, but it reduced the efflux of radioactivity evoked by stimulation of intramural cholinergic nerves. The inhibition of SI efflux in the [3H]‐acetylcholine‐labelled atria may have been mediated by acetylcholine that had accumulated as a consequence of the ant

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00516.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. Prostaglandins (PG) and veratrum alkaloids stimulate ventricular sensory receptors with non‐myelinated vagal afferents and mediate inhibitory circulatory responses.2. The present study in conscious instrumented dogs was carried out to determine the effects of intracoronary artery infusions of veratrine (Ver‐IC) and PGE2(PGE2‐IC) on plasma renin activity (PRA).3. A 15‐20 mmHg decrease in arterial pressure was produced during Ver‐IC (0.2–0.8 μg/kg per min) and PGE2‐IC (10‐50 ng/kg per min), but there was no change in PRA or heart rate.4. In contrast, significant increases in PRA (+ 3.51 ± 0.37 ng angiotensin 1/mL per h;P<0.01) and heart rate (+ 38.5 ± 6.2 beats/min;P<0.001) were elicited in response to a 15–20 mmHg decrease in arterial pressure produced by intravenous infusions of nitroprusside.5. Pharmacological blockade of afferent fibres in the pericoronary region of the left main coronary artery during Ver‐IC resulted in significant hypotension‐induced increases in PRA (P<0.001) and heart rate (P<0.001), thus removing the inhibitory influence of chemosensitive ventricular afferents.6. Therefore, intracoronary veratrum alkaloids and prostaglandins inhibit hypotension‐induced increases in PRA and heart rate in the conscious dog. This is mediated by chemosensitive receptors located in the left ventricular myocardium along with afferent nerves in the pericoronar

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00517.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. In published studies of the effects of acute blood loss in conscious rabbits, the rates of haemorrhage have ranged for 3–9% of blood volume/min. This is potentially a confounding factor when it comes to comparing the results of different studies. We have therefore tested whether the haemodynamic response to acute central hypovolaemia depends on the rate of fall of cardiac output.2. Cardiac output in six conscious rabbits was reduced by 4, 8 and 12% of baseline levels per min by gradual inflation of a cuff around the thoracic inferior vena cava. These rates correspond approximately to blood loss at rates of 3, 6 and 9% of blood volume/min.3. The haemodynamic responses were biphasic. In Phase I (compensatory) there was progressive systemic vasoconstriction and tachycardia, and only a small fall in blood pressure. In Phase II (decompensatory), systemic vasoconstriction failed abruptly, arterial pressure plummeted and heart rate declined.4. We could detect no effect of rate of fall of cardiac output on the pattern of the haemodynamic responses in either Phase I or Phase II.5. We conclude that the rate of blood loss in different studies of haemorrhage in conscious rabbits, within the range 3 to 9 per cent of blood volume per minute, need not be regarded as a confounding factor when it comes to interpreting the results. It is likely that this conclusion can be generalized to studies of haemorrhage in other mammalian specie

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00518.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. The effect of endothelin‐1 on the release of adrenal catecholamines was examined in anaesthetized dogs.2. Splanchnic nerve stimulation (SNS) at 1 and 3 Hz was applied before and after the intravenous injection of endothelin‐1.3. Endothelin‐1 (0.1 and 0.3 μg/kg) significantly enhanced the release of adrenal catecholamines induced by 3 Hz SNS, but did not affect basal release and the release of adrenal catecholamines induced by 1 Hz SNS.4. Endothelin‐1 produced a slight and short‐lasting fall in arterial blood pressure and decreases in adrenal and renal blood flow rates.5. These results indicate that endothelin‐1 enhances the release of adrenal catecholamines from the canine adrenal gland in response to relatively high f

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00519.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY