摘要:

SUMMARY1. The effects of age on α‐adrenoceptor responses, sensitivity and number were studied in rabbits aged from 1 to 36 months.2. Three types of investigation were carried out: conscious animal studies, isolated tissue studies and radioligand binding studies.3. Specific [3H]‐prazosin binding decreased with age in both spleen and heart suggesting that the number of α1‐receptors declined at least in the tissues studied. The specific binding of [3H]‐clonidine to spleen membranes and [3H]‐yohimbine to platelets was not affected by age.4.In vitroresponsiveness to α‐adrenoceptor agonists decreased with age in abdominal aorta and renal artery, while the affinity of adrenoceptors for prazosin (pA2) was not altered. The decrease may be non‐specific as responses to potassium were also altered. No change in α2‐adrenoceptor mediated platelet aggregation was observed.5. No change in pressor or depressor responses to full adrenoceptor agonists or to antagonists was observedin vivo.However, responses to clonidine, which is a partial agonist at α1‐adrenoceptors, were decreased.6. While aging influenced α‐adrenoceptor subtypes differently, there was no direct relation between functional change

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00906.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. The effects ofd‐penicillamine on collagen and total protein synthesis by fibroblast cell cultures were studied.2. High concentration ofd‐penicillamine (10 mmol/1) produced a toxic effect consisting of inhibition of growth and a non‐specific increase in protein synthesis.3. A low concentration ofd‐penicillamine (100 μmol/1) decreased the biosynthesis of both type I and type III c

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00907.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. This study was designed to test the hypothesis that histamine may contribute to the vasodepressor response which occurs in response to physiologic increments in adrenaline concentration in intact animals. Accordingly, following a control period of 30 min, adrenaline was infused intravenously for 45 min at a rate of 250 ng/kg per min in 14 anaesthetized dogs (Group 1).2. A second group of eight dogs received an identical adrenaline infusion following complete H1and H2‐histamine receptor antagonism with tripelennamine plus cimetidine (Group II).3. A time control group of experiments, in which no drugs were infused, as well as groups receiving adrenaline plus either tripelennamine or cimetidine, were also performed.4. In Group I, adrenaline infusion increased heart rate and reduced mean arterial blood pressure by 10 mmHg (P<0.01).5. Following combined H1and H2‐histamine receptor antagonism (Group II), adrenaline infusion failed to reduce mean arterial blood pressure.6. However, mean arterial blood pressure was reduced significantly in the groups receiving adrenaline plus only one of the histamine receptor blocking agents.7. Since only the combined histamine receptor blockade completely eliminated the vasodepressor response to adrenaline, the data suggest that histamine may play a physiological role in the vasodepressor response to circulating adrenaline in the intact animal, and that both H1‐ and H2‐histamine receptors may be i

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00908.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. The effects of metoclopramide on pancreatic exocrine secretion were investigated in the pentobarbitone‐anaesthetized dog. All drugs were injected into the femoral vein.2. Metoclopramide (10–1000 μg/kg) did not change the resting rate of pancreatic secretion.3. Pancreatic secretion, induced by bethanechol (3 μg/kg), was dose‐dependently enhanced by simultaneous injections of metoclopramide (10 and 30 μg/kg), but the protein and bicarbonate concentrations of the pancreatic juice were not affected. Secretions induced by secretin (0.1 units/kg) and dopamine (3 μg/kg) were not modified by metoclopramide at up to 30 μg/kg.4. A larger dose of metoclopramide (1000 μg/kg) suppressed dopamine‐induced secretion to a lesser extent than the same dose of sulpiride.5. From these results, it is concluded that metoclopramide enhances secretory responses to cholinergic stimulations by peripherally sensitizing the muscarinic receptor‐mediated exocrine process and this drug is a weaker antagonist of the dopamine D2receptors

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00909.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. Responses to acetylcholine of isolated perfused hearts obtained from rats which were acutely starved, chronically half‐starved or protein‐restricted were compared with those of paired control groups.2. Isolated hearts of totally starved rats showed no significant change in the responses elicited by 10 and 20 μg doses of acetylcholine as compared with paired controls. With 40 μg acetylcholine a significantly greater reduction (P<0.001) in heart rate and coronary flow was seen and the duration of the negative chronotropic action was significantly increased (P<0.05), as compared with controls.3. Isolated hearts of half‐starved and protein‐restricted rats responded to 10, 20 and 40 μg doses of acetylcholine with significantly greater reduction (P<0.001) in heart rate, coronary flow and increase in duration of negative chronotropic action (P<0.001) as compared t

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00910.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. The pressor responses to angiotensin II injections of 29, 117 and 468 pmol/kg and infusion at 54 pmol/kg per min were compared in near‐term pregnant and matched non‐pregnant rabbits. The responses to noradrenaline injections of 652, 2608 and 10 432 pmol/kg and infusion at 1185 pmol/kg per min were similarly compared.2. At all doses of angiotensin and noradrenaline, whether by injection or infusion, the response of the pregnant animals was significantly greater. However the control arterial pressures of the pregnant rabbits were lower and fell in a range where the baroreceptor reflex might be less effective. Thus less efficient buffering could contribute to the greater response to the vasoconstrictor agents.3. To test the effect of pregnancy on the vascular response to angiotensin and noradrenaline when reflex and central effects were excluded, hexamethonium was used to produce autonomic ganglion blockade. The response to both vasoconstrictors was now less in the pregnant rabbits than in the non‐pregnant.4. Thus in assessing the effects of pregnancy on the responses of the rabbit to angiotensin and noradrenaline the effect of pregnancy on mean blood pressure must be taken into account, since this can influence the extent to which the arterial baroreceptors may modulate the res

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00911.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. The effect of treatment with 9α‐fluorocortisol (9aFF), a steroid which causes hypertension in sheep, was examined in sheep with ACTH‐induced hypertension.2. ACTH treatment alone increased mean arterial pressure (MAP), plasma Na concentration, water intake and urine volume and decreased plasma K concentration.3. 9αFF treatment, for 3 days during continuing ACTH administration, did not change blood pressure but increased heart rate, water intake and urine volume and decreased urinary K excretion.4. As 9αFF did not cause a further increment in blood pressure in sheep with ACTH‐induced hypertension it is possible that both ACTH and 9αFF may produce hypertension by similar m

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00912.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. In normolipidaemic young rats the intraperitoneal administration of diazepam (10 mg/kg) induced a marked fall of the total serum lipids and total cholesterol. A dose of 5 mg/kg brought about an increase of HDL2lipoprotein fraction and an elevation of the HDL2/HDL2.HDL3ratio.2. Margarine administration elicited a significant augmentation of the total serum lipids and a reduction of the HDL2/HDL2.HDL3ratio. The intraperitoneal injection of diazepam in margarine‐treated rats brought about a decrease of total serum lipids and total cholesterol, (when compared to the margarine values), an obvious elevation of the HDL2fraction and of HDL2/HDL2.HDL3ratio. The LDL, (β) fraction was decreased.3. These data confirm our earlier findings which show that diazepam improves the HDL cholesterol/total cholesterol rat

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00913.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. The relationship between active (A) and inactive (I) plasma renin concentrations (PRC) was examined in critically ill patients to test for intravascular renin activation in states of shock and tissue damage.2. Critically ill patients had significantly elevated APRC and lowered IPRC:APRC ratio compared with age and sex matched healthy subjects. IPRC in the critically ill was similar to the control group.3. During blood donation normal volunteers showed a twofold increase in APRC. The rise in APRC was proportionately greater than for IPRC, with a subsequent fall in IPRCAPRC ratio.4. In both critically ill patients and blood donors elevated APRC was associated with decreased IPRC:APRC ratio, consistent with either consumption of the inactive renin zymogen or preferential secretion of the active form. Individual critically ill patients displayed markedly depressed ratios but with only moderately elevated APRC, a pattern suggestive of intravascular renin activation. Consistent evidence for intravascular or extravascular activation of renin was not apparent.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00914.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. The histamine H1and/or H2‐receptor agonists showed weak acetylcholinesterase inhibitory activity. Their dissociation constants (Kisand/or Kii) were 2‐methyl histamine (Kis= 1751 μmol/1, s.e. = 163)<4‐methyl histamine (Kis= 3551 μmol/1, s.e. = 414)

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00915.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY