摘要:

SUMMARY1. Central nervous system stimulants can cause changes in body temperature and changes in susceptibility to high levels of radiofrequency radiation (RFR). In the present study, the effects of the central nervous system stimulant, doxapram, on thermal responses to 2.8 GHz pulsed RFR were examined in anaesthetized rats.2. During intermittent exposure to an average power density of 60 mW/cm2, doxapram significantly increased the time required for temperature to return to the pre‐exposure level when irradiation was discontinued.3. When exposure was continued until lethal temperatures resulted, doxapram administration caused no significant change in survival time when compared to saline controls. Thus, although the drug decreased thermoregulatory efficiency during intermittent exposure to RFR, no change in susceptibility to terminal RFR exposure was observe

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00296.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. Serotonin (5‐hydroxytryptamine) contents of maternal blood, fetal cord blood, and placenta from thirty‐five patients with toxaemia of pregnancy and forty normal pregnant subjects were estimated. Placental monoamine oxidase activity from ten normal and ten toxaemic cases were also estimated.2. An increased content and uptake of serotonin by platelets in maternal blood from toxaemic patients were observed and there was a concomitant reduction in platelet count.3. Raised levels of serotonin and a decrease in monoamine oxidase levels were observed in placentas of the toxaemic group.4. The levels of serotonin in fetal cord blood were significantly higher than those in normal maternal blood. It is suggested that the fetus could be the source of increased serotonin in this syndrome, due to the decrease in monoamine oxidase activity in the toxaemic placenta.5. An abnormality in indole amine metabolism may contribute to the pathology associated with toxaemia of pregna

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00297.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. Airway preparations from the trachea, main bronchi, subsegmental bronchi and the parenchyma of rabbits were studied.2. The proximal airways, the trachea and main bronchi, were less sensitive to histamine than the distal airways of the subsegmental bronchi and lung parenchymal strip.3. The proximal airways were more sensitive to carbachol than the distal airways.4. These results may assist in the interpretation of airway responsesin vivo.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00298.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. Experiments were performed on anaesthetized, open‐chest dogs to determine the reflex effects on systemic blood pressure and heart rate produced by stimulation of the parietal pericardium with bradykinin, prostacyclin, prostaglandin E2(PGE2), prostaglandin D2(PGD2) and arachidonic acid.2. Pericardial application of bradykinin (1 μg) consistently elicited reflex increases in blood pressure and heart rate, whereas application of prostanoids or arachidonic acid in doses up to 10 μg failed to produce any cardiovascular responses.3. Indomethacin, applied either directly to the parietal pericardium (1 μg/ml) or given intravenously (5 mg/kg) caused a long lasting reduction of the reflex responses to bradykinin. The reflex effects of bradykinin could be temporarily restored by treatment of the pericardium with either prostacyclin (0.1 μg/min) or PGE2(0.1 μg/min). PGD2(0.1‐1 μg/min) did not influence the bradykinin induced pericardial reflex.4. Superfusion of arachidonic acid (3 μg/min) over the pericardium amplified the reflex effects of bradykinin when given before, but not when given after indomethacin treatment.5. The results indicate that locally formed prostanoids, specifically prostacyclin and PGE2, can facilitate activation of the pericardial pressor reflex by bradykinin. The findings may be relevant to the changes in cardiovascular activity occurring during pericardial in

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00299.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. Afferent splanchnic nerve stimulation with different frequencies in Wistar Kyoto rats caused depressor and pressor responses depending on the frequency employed.2. Similar visceral afferent activation in spontaneously hypertensive rats caused depressor responses at all frequencies of stimulation.3. It is suggested that the central integrated mechanisms for activating a cardiovascular state change as evoked by visceral afferents may differ in the established hypertensive rat from that of the normotensive.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00300.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. Male rats were treated with a fixed dose of aminoglutethimide (50 mg/kg s.c.) or with progressively increasing doses (50‐100 mg/kg s.c.) for 3 days. Corticosterone levels were found to be decreased in the latter group. Platelet uptake of serotonin as well as the apparent Vmaxwere decreased, whereas the Kmof uptake were increased when compared with that of the control group.2. Addition of ACTH (10 iu/dl) to control rat platelet and corticosterone (10‐80 μg/dl) or triamcinolone (0.5‐5.0 μg/dl) to adrenalectomized rat platelet suspensionin vitrodid not increase the serotonin uptake of the preparation.3. Administration of exogenous dexamethasone (0.05‐0.2 mg/kg i.m.) or triamcinolone (0.05‐5.0 mg/kg i.m.) to adrenalectomized rats, caused a dose related increase in active uptake of serotonin by the platelets. Deoxycorticosterone (0.1‐1.0 mg/kg i.m.) did not have this effect.4. The time course of response to, and the maximum percentage increase in platelet serotonin uptake by, exogenous corticosteroids are related to their glucocorticoid potency.5. The possible role of glucocorticoids on platelet serotonin uptake process

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00301.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. Dose‐response curves to dopamine were obtained on guinea‐pig, dog and human tracheal smooth muscle.2. Dopamine produced a relaxation of the guinea‐pig tracheal chain, and this relaxation was completely blocked by propranolol. The potency of dopamine as a β‐agonist was 1/10 000 that of isoprenaline, 1/250 that of adrenaline and 1/50 that of noradrenaline.3. In human and dog tracheal smooth muscle, dopamine induced a contraction which could be entirely abolished by α‐adrenoceptor antagonists. As an α‐agonist, the potency of dopamine was 1/20 that of adrenaline and noradrenaline.4. Our data also show that a dopamine induced contraction is greatly potentiated if the smooth muscle specimen has been previously slightly contracted with histamine.5. We conclude that there are few, if any, specific dopaminergic receptors in the airways. Dopamine acts on both α‐ and β‐adrenoceptors, but in humans and dogs, its effect is predominantl

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00302.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. Anti‐ulcer and sedative effects of tranquillosedatives viz. benzodiazepines (diazepam, oxazepam and nitrazepam), barbiturate (phenobarbitone), phenothiazines (chlorpromazine, trifluoperazine and thioridazine) and butyrophenone (haloperidol) were compared in albino rats.2. Ulceration of the glandular stomach was induced by 2 h restraint at 4°C. Sedation was measured using the rotarod test.3. These tranquillosedatives showed dose dependent anti‐ulcer and sedative effects. The relative potency and therapeutic index (ratio between rotarod ED50and anti‐ulcer ED50) of each drug were determined. Diazepam showed the highest therapeutic index (1.88).4. Diazepam significantly reduced the volume of gastric secretion, raised its pH and prevented the gastric ulcer formation in pylorus ligated rats but failed to prevent the acute duodenal ulceration induced by intramuscular injection of histamine or carbachol in guinea‐pigs and rats, respectively.5. These observations suggest that benzodiazepines (diazepam) are more suitable anti‐ulcer agents compared to barbiturate, phenothiazines and butyrophenone. The anti‐ulcer effect of diazepam is possibly due to a combination of sedative, anti‐anxiety and antisec

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00303.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. The effects of secretin, cholecystokinin, dopamine, histamine and acetylcholine on the secretion of pancreatic juice were investigated in the monkey and the dog.2. In the resting state, bicarbonate concentration and the volume of pancreatic juice in the monkey were greater than those in the dog. However, the protein concentration of pancreatic juice in the monkey was less than that in the dog.3. Intravenous administration of secretin, cholecystokinin, histamine and acetylcholine caused a dose dependent increase in pancreatic secretion in both species. The responses in the monkey were greater than those in the dog. Dopamine caused pancreatic secretion only in the dog.4. The increase in bicarbonate concentrations of pancreatic juice induced by secretin and histamine in the monkey were greater than that in the dog. Increase in protein concentrations of the juice induced by cholecystokinin and acetylcholine in the monkey were less than that in the dog. However, pancreatic juice pH in both species was the same and was not affected by the secretagogues in the resting state or during the stimulation by secretogogues.5. From these results, it is concluded that there is a species difference in the secretory actions of the secretagogues in the monkey and the dog.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00304.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARY1. The effects of ATP, adenosine and N6‐substituted adenosines, adenosine receptor agonists, on the twitch contraction of guinea‐pig ileum evoked by transmural stimulation were evaluated.2. Adenosine and ATP produced an immediate and concentration dependent inhibition of the twitch, IC50being 1.1 × 10−5mol/l and 1.2 × 10−5mol/l, respectively.3. N6‐l‐phenylisopropyl adenosine (L‐PIA), N6‐cyclohexyl adenosine (CHA) and N6‐allyl adenosine also induced inhibitions which were gradual and persistent, IC50being 2.6 × 10−8, 2.7 × 10−8and 5.4 × 10−7mol/l, respectively.4. Dipyridamole (10−7mol/l), an adenosine uptake inhibitor, markedly augmented the inhibition evoked by adenosine and ATP, but not that by three N6‐substituted adenosines, while theophylline (10−4mol/l) almost completely antagonized the inhibitory effects of all purine compounds. IC50value of adenosine in the presence of dipyridamole (5 × 10−7mol/l) was shifted to the left about 50 times from the control, whereas that of L‐PIA was virtually unchanged.5. Tissue‐medium ratios indicating uptake of [H]adenosine, [3H]ATP and [3H]CHA into the segment were 3.23 (s.e.m. =0.59), 3.59 (s.e.m. =0.78) and 0.41 (s.e.m. =0.04), respectively.6. These results suggest that not only adenosine and ATP but also these N6‐substituted adenosines are potent agonists for the PI receptor, implying a similarity between PI and A, receptor in a functional role and these purine compounds may thereby modulate cholinergic neurotransmis

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1985.tb00305.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY