摘要:

SUMMARY1. Calcitonin gene‐related peptide (CGRP) is a product of alternate splicing of the calcitonin gene. It is found in nerves in the vasculature and is known fromin vitrostudies to be a potent vasodilator. It is found abnormally in the circulation of patients with medullary thyroid carcinoma (MTC) and has been proposed to be a cause of symptoms. This study was designed to determine the dose‐response effects of CGRP infusion in the intact conscious sheep on blood flow to liver and kidney, organs known to be richly innervated by CGRP‐containing nerves.2. Blood flow was measured by an indicator dilution technique using [131I]‐labelled iodohippurate. CGRP infusion at both 1 and 5 pmol/kg per min produced significant (P<0.05) increases in both renal and hepatic blood flow. This increase in flow occurred despite a significant fall in perfusion pressure (P<0.05) at the higher infusion rate. At the highest infusion rate of 10 pmol/kg per min, when fall in perfusion pressure was even more marked, renal and hepatic blood flow was maintained.3. We conclude that CGRP is vasodilatory in the renal and hepatic vascular beds and propose that nerves containing CGRP in those vessels may have a role in maintaining blood flow to those

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1990.tb01346.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SUMMARY1. The forced oscillation technique is a non‐invasive and effort‐independent test used to characterize the mechanical impedance of the respiratory system. Total respiratory impedance was assessed from 4 to 52 Hz in 15 normal subjects breathing air and a helium‐oxygen mixture.2. Breathing helium‐oxygen reduced respiratory resistance and its frequency dependence as well as respiratory reactance very significantly. Resonant frequency during He‐O2breathing was 1.88 times higher than during air breathing.3. It is concluded that by impedance measurement of the respiratory system in normal subjects a density‐dependent decrease of respiratory resistance due to decreased turbulence in the larger airways and a density‐dependent decrease in the inductive reactance can be found during breathing of low density

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1990.tb01347.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SUMMARY1. The time course of recovery of reduced β‐adrenoceptors caused by ovalbumin (OA) challenge was investigated using guinea‐pigs.2. The effects of prednisolone on the recovery time course were also evaluated.3. β‐ and α1‐receptor assays were performed using lung membranes. Adenylate cyclase activity was also measured.4. OA challenge reduced the number of β‐adrenoceptors by 35%, and a significant decrease (13%) persisted for 7 days. The number of β‐adrenoceptors recovered after 14 days.5. OA challenge elevated the number of α1‐adrenoceptors. A significant increase (24%) was observed after 7 days, and it took a further 7 days for the recovery.6. After OA challenge there was a significant decrease in adenylate cyclase activity after 7 days, which recovered after a further 7 days.7. Inhalation of prednisolone accelerated the recovery of β‐adrenergic responsiveness, though it did not affect the recovery of the number of α1‐adrenoceptors. Prednisolone inhalation also elevated β‐adrenergic responsiveness in non‐asthmatic subjects.8. It is concluded that reduced β‐adrenergic responsiveness caused by OA challenge persisted for 7 days and recovered after a further 7 days. Steroid

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1990.tb01348.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SUMMARY1. The antinociceptive properties of the aqueous extract of the intoxicating beverage kava, and of the lipid soluble extract (kava resin) were tested in mice, by the tail immersion and abdominal constriction methods. Both extracts showed analgesic effects in both tests.2. Eight purified pyrones from the lipid soluble extract were also tested for activity in the tail immersion test, and kawain, dihydrokawain, methysticin and dihydromethysticin were found to be very effective in producing analgesia. Using the tail immersion test the time course of action of the extracts of the four effective pyrones of kava were studied.3. Naloxone, in doses which inhibited morphine‐induced analgesia in both tests, was completely ineffective in reversing the antinociceptive activities of the kava extracts, showing that analgesia produced by kava occurs via non‐opiate pathw

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1990.tb01349.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SUMMARY1. The lipid soluble extract of the psychoactive beverage kava has hypnosedative properties which can be measured by the length of time that the righting reflex is lost.2. Ethanol and the lipid soluble extract (kava resin) have been shown greatly to increase each others hypnotic action in mice. Ethanol also increases the toxicity of kava markedly.3. This interaction of kava and alcohol has important clinical and social consequences since, in contrast to traditional usage, kava is now often taken in conjunction with alcoholic drinks.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1990.tb01350.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SUMMARY1. An immunoassay technique employing an enzyme‐labelled ligand was developed for the sulfoxide derivative of the opioid peptide methionine‐enkephalin (MOE).2. The sensitivity of the enzyme immunoassay (EIA) was approximately twofold higher than that achieved in the radio‐immunoassay (RIA) using tritiated ligand. Cross‐reactivities of leucine‐enkephalin and β‐endorphin with the EIA were less than 0.1%, while that with Gly‐Gly‐Phe‐Met and oxidized Gly‐Gly‐Phe‐Met were 2.5% and 10.2%, respectively.3. These results indicate that the EIA is a useful alternative to the RIA for the

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1990.tb01351.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SUMMARY1. Angiotensin II (AII; 0.01 and 0.1 μmol/L), angiotensin I (AI, 0.1 μmol/L) and the β‐adrenoceptor agonist isoprenaline (0.1 μmol/L) all facilitated the stimulation‐induced outflow of radioactivity from slices of rat kidney cortex incubated in [3H]‐noradrenaline.2. Treatment of rats with pertussis toxin (25 and 50 μg/kg i.v.) to inactivate G‐proteins attenuated the facilitation caused by AII and AI, but not that caused by isoprenaline.3. The hypothesis that isoprenaline enhances noradrenaline release by generating AII to activate facilitatory prejunctional AII receptors is not supported by the present study. The hypothesis predicts that pertussis toxin, by inactivating the G‐proteins associated with AII receptors, should have inhibited the facilitatory effect of isoprenaline. This

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1990.tb01352.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SUMMARY1. Naltrindole is a novel δ‐opioid antagonist which is highly potentin vitro.We examined the effects on arterial pressure of naltrindole (0.3–300 pmol) after microinjection into the pressor area of the rostral ventrolateral medulla of chloralose‐anaesthetized rabbits.2. Naltrindole itself had no significant effects on arterial pressure, and only slightly attenuated the hypotensive effect of an exogenous agonist ([d‐Ala2, d‐Leu5]‐enkephalin). This is in contrast to previous demonstration of a marked pressor effect following another δ‐antagonist, ICI 174,864.3. Thus, naltrindole, testedin vivoagainst endogenous opioid effects, does not appear to be as potent as it isin vitro, and in this case was virtua

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1990.tb01353.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY