bluuebunny/crossref_metadata_2025_split huggingface dataset:
FURTHER OBSERVATIONS ON THE PATHOLOGICAL RESPONSES OF RAT SKELETAL MUSCLE TO TOXINS ISOLATED FROM THE VENOM OF THE AUSTRALIAN TIGER SNAKE, NOTECHIS SCUTATUS SCUTATUS
Authors: Harris J. B. , Johnson Margaret A. 
Published: June 2007

SUMMARY1. Some aspects of the response of mammalian skeletal muscle following the injection of purified toxins from the venom of the Australian tiger snake, Notechis scutatus scutatus, are described.2. The toxins used were notexin, notechis II‐5, notechis II‐1 and a modified form of notexin (PBP‐notexin). They were injected into the dorso‐lateral aspect of one hind limb so that the soleus muscle would be exposed to the toxins.3. Within 1 h after the injection of notexin, the soleus muscles were oedematous and by 3–6 h, polymorphonuclear leucocytes had entered the interstitial spaces. The invasion of necrotic muscle fibres was extensive by this time. Muscle spindles appeared relatively unaffected by the toxin.4. The muscle regenerated via myoblasts at 2–3 days to myotubes at 3–5 days, immature muscle fibres at 7–14 days and fully differentiated muscle fibres by 21–28 days. Even after 6 months, however, the nuclei of many muscle fibres remained in a central position.5. A second component of Australian tiger snake venom was also found to be myotoxic. It was slightly less potent than notexin, but caused qualitatively similar damage to that caused by notexin. It was identified as notechis II‐5. A third fraction, notechis II‐l, was found to be inactive.6. Notexin could be neutralized by incubation with tiger snake antivenene; the simultaneous injection of antivenene with notexin did not afford complete protection against muscle damage.
THE EFFECT OF SOME CENTRALLY ACTIVE DRUGS ON CORTICOSTERONE SECRETION AND METABOLISM IN RATS
Authors: Chan Mo Yin , Holmes W. N. 
Published: June 2007

SUMMARY1. Male rats were treated with morphine sulphate (10 mg/kg), methadone (10 mg/kg) and chlorpromazine (8.0 mg/kg) respectively, for 2 weeks.2. At the end of this period, the adrenal glands of treated rats had increased in weight.3. The concentration of corticosterone in the peripheral plasma was significantly lowered in the chlorpromazine‐treated rats, increased in the methadone‐treated rats and was unchanged in the morphine‐treated rats.4. The metabolic clearance rate of [1,2‐3H]corticosterone decreased in the chlorpromazine‐treated rats, while only a slight reduction was observed with methadone treatment.5. These results showed that chronic treatment with either morphine or methadone did not suppress the adrenal function. The possible site of action of chlorpromazine in suppressing corticosterone secretion is discussed.
THE CONTRACTILE RESPONSE OF SMOOTH MUSCLE TO IMMERSION IN HYPERTONIC SOLUTIONS
Authors: Kirkpatrick C. T. , Morrow R. J. , Tomita T. 
Published: June 2007

SUMMARY1. Strips of bovine tracheal muscle and rabbit aorta produced sustained contractions on perfusion with Krebs solution made twice normal strength by addition of sucrose. The contractures were relaxed on return to normal Krebs solution.2. Similar contractures were produced by tracheal muscle strips in Krebs solutions made twice normal strength by addition of galactose, glucose or NaCl whereas urea caused only a transient contraction.3. In twice normal strength Krebs solution (sucrose added) the basal tension of rat portal vein and guinea‐pig taenia coli was increased. Spontaneous mechanical activity was maintained, but the frequency of contractions was reduced.4. The hypertonic contracture of bovine trachea in twice normal strength Krebs solution (sucrose added) was reduced by 15% by omission of Ca from the bathing fluid (01 mmol/1 EGTA added). Severe Ca depeletion, by prolonged washing in Ca‐free Krebs with 12.5 mmol/1 EGTA and Carbachol added, resulted in a 77% reduction in the hypertonic contracture.5. In twice normal Krebs solution (sucrose added), the hypertonic contracture was partially relaxed by isoprenaline (4 × 10−6 mol/1); the contractile response to carbachol was reduced; the contractile response to high‐K Krebs solution was maintained.6. Atropine (5 × 10−7 mol/1) abolished the contractile response to carbachol, but had no effect on the hypertonic contracture.7. It is suggested that the contraction of bovine tracheal strips in hypertonic solutions is mainly due to activation of the contractile myofilaments rather than simple cell shrinkage. Hypertonic solutions may also interfere with some steps in the excitation‐contraction coupling sequence.
ANGIOTENSIN CONVERTING ENZYME IN THE BRAIN OF SPONTANEOUSLY HYPERTENSIVE RATS
Authors: Mendelsohn F. A. O. , Hutchinson J. S. , Csicsmann J. 
Published: June 2007

SUMMARY1. Angiotensin converting enzyme (ACE) was measured in homogenates of regions of rat brain using the substrate Hip‐His‐Leu.2. The enzyme resembled classical ACE in its marked CI” dependence and inhibition by both SQ 20,881 (25 μmol/1) and EDTA (1 mmol/1).3. Spontaneously hypertensive rats (SHR) and normotensive Wistar‐Kyoto controls (NT‐WK) were killed at 20‐22 weeks of age and their brains dissected into eight regions.4. There were marked region variations of ACE with highest levels in striatum, hippocampus, cerebellum and pituitary and lower levels in hypothalamus and cerebral cortex.5. In three brain regions ACE was significantly lower in SHR compared to NT‐WK: medulla oblongata (P<0.05), hypothalamus (P<0‐02) and cerebral cortex (P < 005). In the other sites the levels were not different.6. These region‐specific differences of ACE in the SHR could lead to altered production or metabolism of central neuropeptides postulated to be involved in the control of blood pressure.
EFFECTS OF GOLD SODIUM THIOMALATE ON CYTOSOLIC COPPER AND ZINC IN THE RAT KIDNEY AND LIVER TISSUES
Authors: Sharma R. P. , McQueen E. G. 
Published: June 2007

SUMMARY1. Male Wistar rats were given a single subcutaneous injection of gold sodium thiomalate and killed 7 days later. The binding of Au, Zn and Cu to the kidney and liver cytosolic proteins of control and gold‐treated rats was determined.2. In the renal cytosol of Au(I)‐ exposed rats, the binding of Cu to the low‐molecular‐weight (LMW) proteins increased by 62%, and to the high‐molecular‐weight (HMW) proteins the binding decreased by 54%. The incorporation of Cu into the liver cytosolic proteins increased, in both, the HMW and the LMW proteins. The binding of Zn into the renal cytosolic proteins was increased by 39% (HMW proteins) and 100% (LMW proteins). Au(I) had little effect on the binding of Zn to the cytosolic proteins in the liver.3. It is suggested that the therapeutic action of gold complexes may be mediated, to some extent, by its effects on the metabolism of Cu and/or Zn.
POSSIBLE MEDIATORS OF THE WRITHING RESPONSE INDUCED BY ACETIC ACID OR PHENYLBENZOQUINONE IN MICE
Authors: Baird‐Lambert J. , Jamieson D. D. 
Published: June 2007

SUMMARYDespite widespread use of the writhing response to phenylbenzoquinone or acetic acid injection in mice as a screen for analgesic activity, possible mediators of this response remain unidentified.In the present experiments both in vivo and in vitro techniques have been used in an attempt to identify these mediators.Acetic acid‐induced writhing was unaffected by pretreatment with mepyramine, methysergide, disodium cromoglycate or cimetidine.Phenylbenzoquinone‐induced writhing was partially blocked by pretreatment with mepyramine or other antihistamines.Using guinea‐pig isolated ileum and rat fundus preparations as in vitro assay systems, no significant differences were detected in histamine, serotonin, or prostaglandin content of peritoneal fluid from writhing and control mice.Acetylcholine levels were at the limit of detection in these samples, and there was no evidence of kinin release.Thus the mediators involved in the writhing response remain undefined.
IS FLEMING'S LYSOZYME AN ANALGESIC AGENT? EXPERIMENTS ON MICE
Authors: Bianchi Camillo 
Published: June 2007

SUMMARYAntinociceptive activity of hen egg white lysozyme (Fleming's lysozyme) was determined against abdominal contractions provoked by irritants injected in‐traperitoneally into mice. Carrageenan (2 mg) (CA) injected with arachidonic acid (15 μg) (AA) or prostaglandins PGE1 or PGF2α (0.04 ng), brewer's yeast (10 mg), caolin (10 mg), mepartricin (80 U) and phenylquinone (50 μg) were used as irritants.2 Lysozyme was active at 400‐800 mg/kg i.v. against CA + AA, CA + PG, brewer's yeast and caolin nociceptive stimulation. The compound was more effective against CA + AA than against CA + PG. Acetylsalicylic acid at 50‐100‐200 mg/kg p.o. was equally active against CA + AA and CA + PG.3 Lysozyme was inactive in the tail pinch and hot plate tests that mainly detect central analgesics.4 The results are discussed in relation to the claim advanced years ago that lysozyme is an effective analgesic agent in humans. The compound was found active against herpes zoster or cancer pain but did not find use despite the favourable reports presented.5 The experimental results obtained on laboratory animals do not contradict the conclusions drawn after the clinical use of the compound.
SALT AND WATER INTAKE AND SODIUM AND POTASSIUM EXCRETION IN SPONTANEOUSLY HYPERTENSIVE RATS
Authors: May C. N. , Parsons B. J. 
Published: June 2007

SUMMARYTotal fluid and saline intakes were greater in spontaneously hypertensive rats (SHR) than in normotensive rats (NTR).Total fluid and saline intake were significantly elevated in prehypertensive SHR, 5 weeks old, compared with age‐matched NTR, and the intakes fell with age in both strains but remained considerably greater in SHR.In SHR, in which the blood pressure was maintained at normotensive levels by treatment with hydralazine, the saline and fluid intakes remained elevated above those of NTR.SHR and NTR fed low sodium diet with water alone to drink have similar excretion rates of sodium, suggesting that their ability to conserve sodium was normal.Measurement of sodium excretion after three different levels of sodium loading, on normal or low sodium diets, also failed to demonstrate an abnormality of renal function in SHR.These results demonstrate that the fluid and saline intakes of SHR are elevated compared with NTR and this difference is independent of the hypertension in SHR and is not secondary to enhanced renal sodium loss.
DEPENDENCE OF β‐ADRENERGIC RESPONSIVENESS ON THYROID STATE OF MALE RATS
Authors: Threatte R. M. , Barney C. C. , Baker S. P. , Fregly M. J. 
Published: June 2007

SUMMARY1 The dose of thyroxine (0‐150 μg/kg body weight) administered subcutaneously daily to surgically thyroidectomized male rats was correlated significantly with their metabolic activity as assessed by rate of oxygen consumption and colonic temperature.2 There was a significant dose‐dependent increase in total serum thyroxine, triiodothyronine and reverse‐triiodothyronine concentrations with increasing doses of thyroxine administered.3 The cardiostimulatory response to administration of isoprenaline (8 μg/kg body weight s.c.) was also correlated directly with the dose of thyroxine administered.4 The concentration of cardiac β‐adrenoceptors in these animals was correlated significantly with total serum thyroxine and triiodothyronine concentrations, basal heart rate, and the chronotropic response to administration of isoprenaline.
INFLUENCE OF EXTRA‐INTESTINAL INFLAMMATION ON THE IN VITRO ABSORPTION OF 14C‐GLUCOSE AND THE EFFECTS OF ANTIINFLAMMATORY DRUGS IN THE JEJUNUM OF RATS
Authors: Somasundaram S. , Sadique J. , Subramoniam A. 
Published: June 2007

SUMMARYInflammation was induced in the hind legs of rats by formalin injection and the in vitro jejunal absorption of 14C‐glucose was studied.Treatment of rats with formalin caused a reduction in the in vitro absorption of glucose from the jejunum.Oral administration of oxyphenbutazone or a herbal anti‐inflammatory drug (Withania somnifera) prior to formalin injection, resulted in no alteration in the jejunal absorption of glucose.
A PRELIMINARY STUDY ON PAIN PERCEPTION AND TOBACCO SMOKING
Authors: Milgrom‐Friedman Jeanette , Penman Robyn , Meares Russell 
Published: June 2007

SUMMARY1. Ischaemic pain onset and tolerance in response to a pneumatic blood pressure cuff were compared in 17 non‐deprived smokers, 30 deprived smokers, 15 smokers chewing nicotine gum and 16 non‐smokers.2. Following removal of the cuff, all subjects completed the McGill pain questionnaire, rating pain in terms of its sensory, affective, evaluative and miscellaneous qualities.3. Group differences were found in the time elapsing before reporting the first twinge of pain. Non‐deprived smokers had the shortest period to onset of pain. The longer the smokers had been deprived of cigarettes, the longer before the onset of pain.4. Non‐deprived smokers also had a significantly shorter period of pain tolerance compared to deprived smokers.5. Non‐deprived smokers tended to have a faster pain onset and a shorter tolerance period compared to non‐smokers.6. Smokers’ indices of pain were significantly higher on the several sub‐scales describing the qualitative pain experience compared to non‐smokers and to smokers deprived of cigarettes for more than one hour.7. Deprivation of cigarettes appears to diminish smokers’ sensitivity to pain significantly below that of non‐smokers and smoking cigarettes tends to heighten sensitivity to, or beyond, the level of non‐smokers.
EFFECTS OF A NON‐VASOCONSTRICTOR DOSE OF PHENYLEPHRINE ON PROSTAGLANDIN E2 AND RENIN RELEASE IN ANAESTHETIZED DOGS
Authors: Hisa H. , Satoh S. 
Published: June 2007

SUMMARYPhenylephrine (1 μg/min) was infused into the renal artery of pentobarbitone anaesthetized dogs. Systemic blood pressure and renal blood flow were monitored. Arterial and renal venous blood samples were collected before and 10 min after the start of the infusion. Plasma prostaglandin E2 concentration and plasma renin activity were measured by radioimmunoassay.This dose of phenylephrine did not affect systemic blood pressure and renal blood flow.However, both prostaglandin E2 and renin secretion rates were increased by the infusion of phenylephrine.These results suggest that renal α‐adrenoceptors participate in prostaglandin and renin release independent of the changes in systemic blood pressure and renal blood flow.
HAEMODYNAMIC EFFECTS OF PRENALTEROL IN ACUTE MYOCARDIAL ISCHAEMIA IN OPEN CHEST PIGS
Authors: Branzi A. , Binetti G. , Specchia S. , Hi C. Mage , Zannoli R. , Magnani B. 
Published: June 2007

SUMMARY1. The haemodynamic effects of prenalterol, a new sympathomimetic agent, have been studied in anaesthetized open‐chest pigs with acute myocardial ischaemia provoked by left anterior descending coronary artery ligation. A group of eight animals was infused with saline and served as control (C).2. In both groups the ligation of the left anterior descending coronary artery determined a significant (P<0.05) reduction of aortic flow, maximum left ventricular (LV) dp/dt with no changes in heart rate.3. The infusion of a first dose of 30 &#x006d;̈g/kg of prenalterol restored the depressed haemodynamics but increased significantly the heart rate in the prenalterol group while the saline infused group did not show any significant changes. The haemodynamic effects of prenalterol were still evident 25 min after the infusion.4. The subsequent administration of a second dose of 60 &#x006d;̈g/kg of prenalterol resulted in a further improvement of the aortic flow, LV dp/dt and heart rate which reached values higher than in the basal condition.5. The positive inotropic effect was not associated with changes in stroke volume, therefore the increase in aortic flow was essentially due to an increase of the heart rate.6. It is concluded that prenalterol is a powerful inotropic agent in acutely infarcted animals. Its action on aortic flow appears to be related to an increase in heart rate in contrast to some previous observations.
ENDOGENOUS VASOPRESSIN MODULATES THE BAROREFLEX SENSITIVITY IN RATS
Authors: Imai Yutaka , Nolan Peter L. , Johnston Colin I. 
Published: June 2007

SUMMARY1. The effect of endogenous vasopressin on the baroreceptor reflex has been examined by comparing baroreflex function in Brattleboro rats with hereditary hypothalamic diabetes insipidus (DI rat) with that in Long‐Evans rats (LE rat).2. Baroreflex function was assessed in conscious unrestrained rats during increases in blood pressure with phenylephrine.3. The slope of the baroreflex function line in LE rats [(19.0, s.e.m. = 1.4) × 10‐4, n = 34] was significantly steeper than that in DI rats [(6.9, s.e.m. = 0.6) × 10‐4, n = 44, P< 0.0001].4. A subpressor infusion of arginine8‐vasopressin (2 ng/kg per min for 2 h i.v.) and an equidose of DDAVP caused bradycardia and increased the baroreflex function slope significantly.5. Acute volume expansion in DI rat did not change the baroreflex sensitivity.6. A specific vasopressin vascular receptor antagonist, d(Ch2)5Tyr(Me)AVP, did not alter the baroreflex sensitivity in LE rats.7. These results suggest that endogenous vasopressin is an important physiological regulator of the baroreflex sensitivity in normal rats.
INTENSE VASOCONSTRICTION AND BRADYCARDIA EVOKED BY STIMULATION OF NEURONES WITHIN THE MIDBRAIN VENTRAL TEGMENTUM OF THE RABBIT
Authors: Tan Esther , Goodchild A. K. , Dampney R. A. L. 
Published: June 2007

SUMMARY1. Electrical stimulation of sites in the midbrain ventral tegmental area (VTA) and the lateral hypothalamic area of the anaesthetized rabbit elicited intense vasoconstriction and profound bradycardia.2. The same effects were elicited by microinjections of glutamate ions into the VTA but not the lateral hypothalamic area.3. Following baroreceptor denervation, the bradycardic component of the response was greatly reduced, but the vasoconstrictor component was unaffected.4. It is concluded that the cardiovascular response is generated by excitation of a cell group within the VTA, but within the hypothalamus the response arises from excitation of axons of passage.
THE EFFECT OF THE CALCIUM ION ANTAGONIST 8‐(N,N‐DIETHYLAMINO)‐OCTYL‐3,4,5‐TRIMETHOXYBENZOATEON MALIGNANT HYPERPYREXIA‐SUSCEPTIBLE PORCINE SKELETAL MUSCLE
Authors: Sullivan J. S. , Galloway G. J. , Denborough M. A. 
Published: June 2007

SUMMARY1. In malignant hyperpyrexia susceptible (MHS) porcine skeletal muscle, a low concentration (100 μmol/1) of the calcium ion antagonist 8‐(N,N‐diethyl‐amino)‐octyl‐3,4,5‐trimethoxybenzoate (TMB‐8) inhibited KCl‐induced contractures, but potentiated contractures induced by halothane, caffeine and succinylcholine.2. Higher concentrations of TMB‐8 (333 μmol/1 to 1 mmol/1) contracted MHS muscle, but had little effect on muscle tension in control preparations.3. Treatments which inhibit excitation‐contraction coupling abolished TMB‐8‐induced hyper‐reactivity in MHS muscle.4. TMB‐8 (50 μmol/1 and 1 mmol/1) did not alter 45Ca2+ levels in actively loaded microsomal preparations from MHS swine.5. These results suggest that in malignant hyperpyrexia the primary abnormality occurs proximal to the release of calcium from the sarcoplasmic reticulum, probably at the level of excitation‐contraction coupling.
QUANTITATIVE STRUCTURE‐ACTIVITY RELATIONSHIPS OF IMIDAZOLIDINE DERIVATIVES RELATED TO CLONIDINE AT PERIPHERAL α‐ADRENOCEPTORS
Authors: Medgett I. C. , McCulloch M. W. 
Published: June 2007

SUMMARY1. The effects of clonidine, oxymetazoline and thirteen substituted phenyl‐iminoimidazolidine analogues of clonidine were studied and compared on postjunctional α‐adrenoceptors in guinea‐pig and rabbit aorta and on prejunctional α‐adrenoceptors in guinea‐pig atria.2. In the aorta all compounds were partial agonists at postjunctional α‐adrenoceptors. Correlation of agonist potency with various combinations of their physicochemical parameters showed that, with the present series of compounds, physicochemical parameters alone determined 92% of the variance in the data with potency being primarily and highly correlated with pKa.3. Similarly in atria, all compounds, with the possible exceptions of St 95 and St 1943, appeared to be partial agonists at prejunctional α‐adrenoceptors; transmitter noradrenaline release could either be inhibited (field stimulation at 1 Hz for 5 s) or enhanced (5 Hz for 30 s).4. The results indicate that 2,6‐substitution in the phenyl ring appears to be a specific non‐physicochemical activity‐enhancing factor at prejunctional but not postjunctional α‐adrenoceptors.5. A comparison with data in the literature giving the acute hypotensive potencies of the compounds suggests that central α‐adrenoceptors may more closely resemble atrial prejunctional α‐adrenoceptors than aortic postjunctional α‐adrenoceptors.6. Quantitative correlations between centrally‐mediated hypotensive and peripheral vasoconstrictor effects of clonidine‐like imidazolidines do not provide a sufficiently sensitive method of distinguishing between a‐adrenoceptor subtypes.
EFFECTS OF ADRENALECTOMY AND ADRENAL STEROIDS ON THE UPTAKE OF SEROTONIN IN RAT PLATELETS
Authors: Lee P. H. K. , Chan Mo‐Yin 
Published: June 2007

SUMMARY1. Changes induced by adrenalectomy, triamcinolone treatment and deoxycorticosterone (DOC) treatment on the uptake of [3H]‐serotonin into platelets were studied ex vivo, using rat platelets suspended in physiological medium.2. Adrenalectomy caused a decrease in active uptake of serotonin and an associated increase in apparent Km.3. Treatment of the adrenalectomized rats with triamcinolone (0.25 mg/kg), but not DOC (1.0 mg/kg) restored the active uptake of serotonin.4. At triamcinolone dose of 0.5 mg/kg, the serotonin uptake was raised to a level that was significantly higher than normal.5. Kinetic analysis of uptake data showed the apparent Km, to be affected by both triamcinolone and DOC, while the apparent Vmax of uptake rate was increased by triamcinolone treatment.
SUPINE HYPERTENSION, BLOOD PRESSURE VARIABILITY AND CIRCADIAN RHYTHM IN AUTONOMIC FAILURE: THE ROLE OF AMBULATORY INTRA‐ARTERIAL MONITORING
Authors: Mann Stewart , Bellamy G. R. , Hunyor S. N. , Raftery E. B. , Ingall T. , Bannister R. 
Published: June 2007

SUMMARY1. Blood pressure variation over 24 h was studied in twelve subjects with suspected or established autonomic failure using ambulatory intra‐arterial monitoring.2. Three subjects who had been previously diagnosed as having orthostatic hypotension due to autonomic failure were found to have normal circulatory reflexes.3. A generally consistent circadian variation of blood pressure was seen in the other nine subjects, pressure rising gradually from its lowest point early in the morning to a peak during the early part of the night; this pattern was also found during bed rest in four subjects.4. Supine hypertension (an hourly mean blood presure of > 170/90 mmHg) not suspected from sphygmomanometric readings was observed in four subjects, generally during the night.5. Heart rate variability was reduced in six subjects while short‐term blood pressure variability was markedly increased.