Intracerebroventricular injection of prostaglandin E(1) changes concentrations of biogenic amines in the posterior hypothalamus of the rat

Since the posterior hypothalamus (PH) plays a key role in the control of body temperature, the aim of this study was to evaluate the changes in adrenaline, noradrenaline and dopamine levels in the PH during the hyperthermia induced by prostaglandin E(1) (PGE(1)). The concentration of adrenaline, noradrenaline and dopamine in the PH, the firing rate of the sympathetic nerves innervating interscapular brown adipose tissue (IBAT), IBAT and colonic temperatures (T(IBAT) and T(C)) were monitored in 12 urethane-anaesthetized male Sprague-Dawley rats before and after an intracerebroventricular injection of 500 ng PGE(1) dissolved in 2 microl of 0.9% NaCl saline solution or only saline. The catecholamines were collected using a microdialysis probe and quantified by HPLC. The results showed that PGE(1) caused a significant increment in the concentration of adrenaline from 15. 83+/-2.69 to 34.95+/-3.9 ng ml(-1) and of dopamine from 35.15+/-4.48 to 55.68+/-6.21 ng ml(-1). A significant decrease in the level of noradrenaline from 18.75+/-2.05 to 8.56+/-2.26 ng ml(-1) was registered. The firing rate of sympathetic nerves to IBAT was increased from 100+/-0% to 204.83+/-15.22% by PGE(1). T(IBAT) and T(C) rose respectively from 36.91+/-0.15 degrees C to 38.88+/-0.29 degrees C, and from 36.7+/-0.15 degrees C to 38.13+/-0.36 degrees C after the injection of PGE(1). The changes in adrenaline and noradrenaline occurred during the first 20 min as did the changes in temperature and firing rate, while the change in dopamine was delayed until 21-60 min after the PGE(1) injection. No significant change of analyzed variables was found in the control rats. These findings suggest that these biogenic amines of the PH are involved in the control of the sympathetic and thermogenic changes induced by PGE(1).     

Pulsatile release of catecholamines in the hypothalamus of conscious rats

Summary To investigate the patterns of catecholamine release in the brain, the hypothalamus of conscious, freely moving rats was superfused through a push-pull cannula with artificial cerebrospinal fluid and the catecholamines dopamine, noradrenaline and adrenaline were determined in the superfusate radioenzymatically. Superfusate was continuously collected in time periods of 20 min for at least 20h. Dopamine, noradrenaline and adrenaline release rates fluctuated according to an ultradian rhythm with a frequency of 1 cycle/92 min (dopamine and noradrenaline) or 99 min (adrenaline). Additionally, the three catecholamines were released according to an ultradian rhythm with the following frequencies: noradrenaline and adrenaline 1 cycle/ 12 h, dopamine 1 cycle/8 h. The release rates of dopamine and adrenaline were similar during light and dark periods, while the release rate of noradrenaline in the dark period was slightly lower than that during the light period. It is concluded that in the hypothalamus of the conscious rat the release rates of dopamine, noradrenaline and adrenaline fluctuate according to two ultradian rhythms with different frequencies.This work was supported by the Deutsche Forschungsgemeinschaft and the Fonds zur Förderung der wissenschaftlichen ForschungParts of this work have been presented at the 29th Spring Meeting of the German Society of Pharmacology and Toxicology, 1988 and at the 12th Annual Meeting of the European Neuroscience Association, 1989Correspondence to H. Prast at the above address     

The effect of adrenaline,tyramine and guanethidine on two-way avoidance conditioning and on pseudoconditioning

Adrenaline (0.5 mg/kg) or guanethidine (10 mg/kg) given i.p. depressed performance of pseudoconditioned shuttle responses by rats. In a previous paper it had been shown that tyramine (5 mg/kg) had an opposite effect (Izquierdo, 1974a). Pre-trial administration of any of the three drugs also depressed two-way avoidance conditioning. Following posttrial administration, only guanethidine had a deleterious effect on reténtion. Since none of these drugs is believed to reach the brain in significant amounts following systemic injection, the present results suggest that peripheral factors may influence both conditioned and pseudoconditioned shuttle behavior.     

Lowering of kininogen in rat blood by catecholamines

Summary Catecholamines lower the kininogen content of rat blood in vivo and in vitro. Blood cells are required: these are neither erythrocytes, lymphocytes, eosinophils nor platelets but could be neutrophils or basophils.The bovine protease inhibitor (Trasylol^®) inhibits the effects of l-adrenaline in vivo and in vitro but fails to affect the action of cellulose sulfate on rat plasma kininogen by more than a small extent.     

Consistency in catecholamine and cortisol excretion in males and females

Data from a series of experiments performed on 24 female and 24 male subjects were used to evaluate the consistency in urinary catecholamine and cortisol excretion. Data were available from 8 laboratory situations of varying activity level and content, spaced at intervals of maximum 3 months. Correlational analyses showed that for cortisol, interindividual consistency was higher for measures obtained on the same day than for measures obtained on different days. Interindividual consistency was generally high in catecholamine and cortisol excretion during non-stressful situations in both sexes. During experimental stress, however, consistency was as high as during nonstress for males, while it was lower for females. Analysis of variance components confirmed these results and showed that in males variation due to interindividual differences was high during both baseline and experimental-stress situations, while in females it was high during baseline situations only. During experimental stress, variation for females was due primarily to interaction. It is suggested that the males showed a more generalized stress response over situations than the females.     

Activation of natural killer cell function in recreational athletes with paraplegia during a wheelchair half-marathon race

OBJECTIVE: To investigate a part of the immune homeostasis in recreational athletes with spinal cord injury (SCI) during and after a wheelchair half-marathon race. DESIGN: Case-control study in an actual race. SETTING: The half-marathon division of an international wheelchair marathon race in Japan. PARTICIPANTS: Seven male wheelchair racers with SCI between T7 and L1. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Changes in the number and function of natural killer (NK) cells and the endocrine effects, including plasma catecholamines and cortisol in blood samples obtained the day before the race, immediately after it, and 1 day after the race. RESULTS: Both the percentage and absolute number of peripheral NK cells did not change significantly throughout the experiment. Mean NK cell cytotoxic activity +/- standard deviation increased significantly, from 45.5%+/-7.5% to 56.1%+/-5.1% (P<.01) immediately after the race and remained increased until the next day. Plasma adrenaline levels were increased (P<.05) immediately after the race and recovered 1 day later; the plasma concentration of cortisol did not change throughout the experiment. CONCLUSIONS: The wheelchair half-marathon race induced activation of NK cell function in recreational athletes with SCI between T7 and L1.     

Desensitization of the platelet aggregation response to adrenaline during insulin-induced hypoglycaemia in man

The aim of the present study was to investigate the influence of insulin-induced hypoglycaemia on platelet sensitivity to adrenaline and non-adrenergic agonists in man. Twenty-five healthy male subjects volunteered for the study. To evaluate the effects on platelets of different insulin-adrenaline interrelationships, two experimental models were used. In the first, hypoglycaemia was induced by a 60-min IV infusion of human insulin at the rate of 64 mU m-2 min-1, whereas in the other the same insulin dose was administered as an IV bolus (3.84 U m-2). Throughout the studies, plasma glucose, insulin, and adrenaline were measured together with platelet sensitivity to adrenaline, ADP, platelet activating factor, collagen, and sodium arachidonate. In both studies, hypoglycaemia induced a reduction of platelet sensitivity to adrenaline (p = 0.006 in infusion and p = 0.045 in injection study). In particular, maximal aggregation to adrenaline fell from 47.9 +/- 9.9 (+/- SE) to 31.1 +/- 11.3% at the hypoglycaemic nadir in the infusion study, and from 64.6 +/- 8.2 to 34.6 +/- 10.3% at the hypoglycaemic nadir in the injection study. In the injection study an increase of platelet sensitivity to ADP (p = 0.05), platelet activating factor (p = 0.018), sodium arachidonate (p = 0.035), and collagen (p = 0.027) was also found, in agreement with observations already published using the infusion protocol. Thus, insulin-induced hypoglycaemia increases platelet sensitivity to non-adrenergic agonists and decreases platelet response to adrenaline.     

The effect of a priming epidural injection of adrenaline on epidural blockade with bupivacaine

Twenty-four patients receiving epidural anaesthesia were studied to test the hypothesis that 1:200,000 adrenaline administered into the epidural space 5 minutes before 20 ml bupivacaine 0.5% would improve nerve block and delay systemic absorption of the local anaesthetic. Group A/B received 20 ml adrenaline 1:200,000 5 minutes before 20 ml bupivacaine 0.5%, group S/BA 20 ml saline followed by 20 ml bupivacaine 0.5% with 100 micrograms adrenaline, and group S/B saline 20 ml followed by 20 ml plain bupivacaine 0.5%. Mean maximum plasma concentrations of bupivacaine tended to be lower in the adrenaline groups. A delay in the time to peak plasma concentration of bupivacaine was noted in the A/B group; this indicated that priming with adrenaline may be effective at delaying early systemic uptake of the local anaesthetic. In both adrenaline groups a more prolonged epidural block and increased efficacy were noted, although this was only significant for the duration of block at T6 (p = 0.023) and duration of motor block at Bromage level 1 (p = 0.016) in group A/B. There seems little clinical advantage in administering adrenaline 5 minutes before bupivacaine.     

Neither adrenergic nor cholinergic antagonists in the central nervous system affect 2-deoxy-d-glucose(2-DG)-induced hyperglycemia

To investigate whether the brain adrenergic and cholinergic neurotransmitter systems are involved in the regulation of 2-deoxy-d-glucose (2-DG)-induced hyperglycemia, we studied the effects of adrenergic and cholinergic antagonists on 2-DG-induced secretion of epinephrine and glucagon, and hyperglycemia, in anesthetized fed rats. When 2-DG (10 mg/10 μl) was injected into the third cerebral ventricle, hepatic venous plasma glucose, glucagon, and epinephrine concentrations were significantly increased. Co-administration of phentolamine, propranolol, atropine and hexamethonium (1 × 10⁻⁷ mol) with 2-DG did not modify the hyperglycemia responses normally observed after the administration of 2-DG alone. From this evidence we concluded that neither brain adrenoceptive nor cholinoceptive neurons are involved in the regulation of 2-DG-induced hyperglycemia.     

氧气驱动雾化吸入肾上腺素佐治毛细支气管炎

目的观察氧气驱动雾化吸入肾上腺素佐治毛细支气管炎的疗效.方法157例毛支炎患儿随机分为二组,对照组77例,用复方氯喘片治疗;治疗组80例,用6 L/min氧气驱动雾化吸入肾上腺素每次0.4～0.6 mg/kg,雾化吸入15 min,每日2～3次.两组其他常规如抗感染、吸氧等对症处理相同.观察两组临床症状体征消失时间.结果治疗组有效率83.7%,明显优于对照组48.1%,(P＜0.01).结论氧气驱动雾化吸入肾上腺素是佐治毛支炎安全有效的方法之一.