ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00941.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. Prostaglandin (PG) efflux into ureteral (UE) and venous effluents (VE) of rabbit isolated perfused kidneys was determined by superfusion bioassay and radioimmunoassay (RIA), in response to injections of arginine‐vasopressin (AVP), the non‐pressor vasopressin analogue 1‐deamino‐8‐D‐arginine vasopressin (dDAVP) and arachidonic acid (AA).2. dDAVP (10–1000 ng) failed to stimulate renal PG release, whereas AVP (10–100 ng) and AA (10–50 μg) caused a dose‐dependent release of PG.3. AVP evoked PG release into both effluents with release into the VE greater than UE at high doses. In contrast, PG release by AA was almost exclusively into the VE.4. Indomethacin (2.8 × 10‐6mol/1) abolished AVP‐ and AA‐induced PG efflux in both effluents, and vasodepressor responses to AA.5. PGE2was the predominant PG released in response to AVP in both effluents whereas AA released primarily 6‐keto‐PGF1α.6. The contrasting sites and profile of released PG suggest that exogenous AA and AVP stimulate the release of PG from different regi

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00942.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. Mean‐arterial pressure (MAP), heart period (HP) and the level of physical activity were measured in conscious rabbits and averaged over one‐hour periods during 14 consecutive days. Serial autocorrelation coefficients and serial crosscorrelation coefficients were computed, to analyse periodicity.2. Measurements were started immediately after implantation of the cannula (group A,n= 11) or 10–46 days after implantation of the cannula (group B,n= 6).3. In the course of 14 days, in group A, MAP decreased 9 mmHg and HP increased 21 ms (P<0.05). In group B, MAP decreased and HP increased in a similar way. Percentage activity did not show a trend.4. Significant diurnal rhythms were found. MAP and percentage activity reached the lowest values at noon, and the highest late in the evening. HP reached the highest values at noon and the lowest late in the evening. MAP and HP fluctuated exactly in antiphase. This suggests a common origin for both rhythms.5. During physical activity MAP was 10–15 mmHg higher and HP was 35–40 ms shorter than during rest. These differences did not show a trend or a diurnal variation.6. In individual animals MAP and HP varied greatly from hour to hour.7. These biological variations in MAP and HP as well as the influence of activity should be taken into account when conclusions are drawn from short‐term m

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00943.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. The cardiovascular effects of trimazosin, a quinazoline derivative similar in structure to prazosin, were investigated and compared with prazosin in the rabbit.2. Radioligand binding to cerebral membranes showed that trimazosin has roughly 100‐fold less affinity for the α1‐adrenoceptor. This was further supported by its lower pA2derived from phenylephrine contractile responses in isolated thoracic aorta preparations.3. Trimazosin is less extensively distributed and has a lower clearance from whole blood than prazosin although their whole blood elimination half‐lives are comparable. In addition, although it is a less potent α1‐adrenoceptor antagonistin vivo, its peripheral vascular depressor effect tends to be greater than prazosin.4. Trimazosin at the dose used and under the conditions of study did not reverse the peripheral pressor effect of angiotensin II or B‐HT920 but at higher concentrations, unlike prazosin, it relaxed the K+contracted thoracic aorta. In addition, following pharmacological autonomie blockade and treatment with prazosinin vivo, trimazosin caused a further depressor response. A similar though shorter lasting non‐α1‐receptor mediated action was also observed with prazosin.5. 1‐Hydroxytrimazosin (CP23445), the major metabolite of trimazosin in man, showed little affinity for either the α1‐ or α2‐adrenoceptor from radioligand binding studies.6. In addition to α1‐adrenoceptor antagonism, trimazosin may exert an additional direct va

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00944.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. The effect ofl‐thyroxine on serum angiotensin converting enzyme activity using a sheep model was examined.2. Following two weeks ofl‐thyroxine treatment, the activity of serum angiotensin converting enzyme was increased from 6.92 U/ml to 8.65 U/ml (s.e.m. = 0.40,n= 13,P<0.01).3. Discontinuation ofl‐thyroxine treatment resulted in lowering the activity of serum angiotensin converting enzyme within three weeks to values close to those observed during the control period.4. It was concluded thatl‐thyroxine modulates serum angiotensin converting enzyme activity. The sheep is an appropriate animal model for the study of the factors that control serum angiotensin converting enzyme a

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00945.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. Responses of the toad isolated rectus abdominis muscle to cumulative doses of carbachol were recorded in the absence or presence of varying concentrations of cimetidine or ranitidine. The corresponding cumulative log concentration‐response curves for carbachol were then plotted for each antagonist studied.2. Cimetidine (1 mmol/1) produced a straight and parallel 1.8‐fold shift of the carbachol curve to the right of the corresponding control curve with no significant change in the maximal response.3. Cimetidine, at doses of 2.5 mmol/1 and 5 mmol/1, and ranitidine, at doses of 0.1 mmol/1, 0.25 mmol/1 and 0.5 mmol/1, produced a concentration‐dependent and non‐parallel shift of the carbachol curve to the right of the corresponding control curve accompanied by a marked decline of maximal responses.4. The results provide further evidence that ion‐channel block may be involved in the neuromuscular blockade produced by cimetidine or ranitidine, the latter being more potent in this respect. Competitive antagonism may also be partly responsible for cimetidine‐induced neuromuscular blockade, especially at lower drug con

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00946.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. The cardiohaemodynamic response and the development of tolerance to isosorbide dinitrate (ISDN) were examined in anaesthetized, open‐chest dogs.2. ISDN, infused intravenously (i.v.) for 2 h at a rate of 10 or 30 μg/kg per min, decreased systemic blood pressure (systolic, mean and diastolic; SBP), left ventricular (LV) systolic and end‐diastolic pressure, LVdP/dt max, pressure‐rate product and coronary blood flow. No significant changes in heart rate (HR) and coronary vascular resistance were observed.3. Intravenous ISDN significantly attenuated the vasodilator effect of bolus intra‐coronary (i.a.) glyceryl trinitrate (GTN, 1 μg), and ISDN (30 μg), whereas that of bolus i.a. nicorandil (mononitrate, 20 μg) remained unaffected.4. Just after acute tolerance towards i.a. ISDN was provoked 1 h after starting ISDN infusion (30 μg/kg per min, i.v.), the combined infusion of ISDN (i.v.) and nicorandil (30 μg/kg per min) was instigated for a further hour. Also, 1 h after the onset of vehicle infusion (i.v.), the combined infusion of vehicle and nicorandil (30 μg/kg per min, i.v.) was started.5. There were essentially no significant differences between the corresponding values concerning the coronary vascular responses obtained from the two combined i

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00947.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. Thromboxane A2and prostacyclin are two compounds which have been implicated as important modulators of local cerebral blood flow.2. Concentrations of the stable metabolites of these two compounds, thromboxane B2and 6‐keto‐PGF1α, were measured in cerebrospinal fluid (CSF) from eight acute ischaemic stroke patients and 14 patients with no evidence of cerebrovascular disease.3. Concentrations of thromboxane B2ranged from 0.15 to 4.0 pg/ml and were significantly higher (P= 0.025) in the ischaemic stroke group when compared with the control group (0.1–0.3 pg/ml). Simultaneously acquired concentrations of 6‐keto‐PGF1α were not elevated in the stroke group when compared to normals.4. These clinical findings support evidence from animal studies that emphasizes the importance of cerebral prostaglandins in mediating the secondary vascular changes of cerebral infarction. In conclusion there is an aberration in CSF thromboxane B2concentrations in patients who have had a stroke. This may be an acute or chronic

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00948.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The Molecular Basis of Cancer.Edited by Peter D. Farmer and John M. Walker.Drug Treatment of Neurotic Disorders‐Focus on Alprazolam.Edited by Malcolm H. Lader.Pharmacotherapy of Affective Disorders: Theory and practice.Edited by W. G. Dewhurst and G. B. Bake

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00949.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY