摘要:

Experiments were performed in chloralosed cats, laparotomized with ligated adrenals and spinalized in the cervical region. Blood pressure, heart rate and gastric motility were monitored. Stimulations were performed in two brain stem regions, viz. a “control region” including the nucleus ambiguous and a “dorsal region” approximately corresponding to the dorsal vagal nucleus and the solitarius complex. From both regions were regularly elicited gastric motor responses that were either excitatory, biphasic or inhibitory in direction, and always associated with prompt bradycardia and hypotension. After hexamethonium blockade of the “conventional” efferent vagal excitatory and relaxatory fibres to the stomach, stimulation of the control region no longer augmented gastric motility, while gastric contractions which could be abolished by atropine or vagotomy were produced from the dorsal region. The bradycardia and hypotension responses from both regions were also blocked by hexamethonium and then stimulations often led to delayed pressor responses, resistant to both vagotomy and atropine. The present results, together with previous findings (Delbro et al. 1981, 1982) suggest that the hexamethonium‐resistant gastric contractions, elicited by stimulation of the mentioned dorsal region of the brain stem, are due to antidromic activation of afferent gastric vagal fibres with excitatory collaterals to intramural cholin

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb10591.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Erythrocyte 2,3‐DPG, PO250%, whole blood hemoglobin and available O2, and fixed acid Bohr effect were studied during the first 10 days after birth in rapidly growing suckling rabbits. The post‐natal fall in hemoglobin concentration was accompanied by a marked rise in erythrocyte 2,3‐DPG and a gradual increase in PO250%. The rise in PO250% was sufficient to keep the available O2of the blood unchanged throughout the observation period. The observations show that a 2,3‐DPG mediated rise in PO250% very effectively contributes to maintenance of adequate tissue oxygenation during the post‐natal fall in hemoglobin. The rise in 2,3‐DPG and PO250% may be due to the ordinary hypoxia‐induced shift to the right of the hemoglobin O2dissociation curve, as observed under other circumstances when blood hemoglobin is rapidly reduced, but the very marked rise in 2,3‐DPG and the very low Δ PO250%/Δ 2,3‐DPG ratio suggest that the rise may as well be due to hypoxia independent, pre‐programmed processes. The fixed acid Bohr effect was essentially the same in newborn and adult rabbits, and was uninfluenced by large

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb10592.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The function of lumbar back muscles was studied by relating their activity patterns to trunk movements in 7 healthy adult males during normal walking (1.0–2.5 m/s) and running (2.0–7.0 m/s) on a treadmill. The movements of the trunk in the sagittal and frontal planes were recorded with a Selspot optoelectronic system using infrared light emitting diodes as markers. The electromyographic (EMG) activity from the two main portions of the lumbar erector spinae muscles (Multifidus and Longissimus) was recorded bilaterally with intramuscular wire electrodes. The angular displacements of the trunk showed regular oscillations, but their shape, magnitude and relation to the step cycle were different in the two planes (sagittal and frontal) and varied with speed and mode of progression. The EMG pattern in both muscles showed a bilateral cocontraction with two main bursts of activity per step cycle starting just before each foot was placed on the ground. Relating the EMG to the movements of the trunk indicated that the main function of the lumbar erector spinae muscles is to restrict excessive trunk movements. During walking this restricting action is most evident for movements in the frontal plane, whereas in running the lumbar back muscles mainly control the movements in the sagittal pl

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb10593.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The regional capacity of the blood‐brain barrier (BBB) has been investigated in rat brain during normal conditions and after acute immobilization (IMO). The BBB function was monitored by fluorescence microscopical localization of systemically administered vital dye (trypan blue) and by studying the ability of the brain capillaries to decarboxylate and trap injected L‐DOPA. The results demonstrated clear signs of dye penetration into the parenchyma of certain brain regions (area preoptica, some hypothalamic nuclei, area ventralis tegmenti and ventral part of the pons and medulla oblongata) in addition to the areas known to be ‘outside the BBB’ (the circumventricular organ). There was an apparent increase in dye penetration in these regions after IMO, most pronounced in the reticular formation of the brain stem. In the mesencephalic reticular formation ruptures of a substantial number of vessels occurred after IMO leading to massive leakage of dye into surrounding brain parenchyma. The main finding after L‐DOPA administration was indications of a more efficient decarboxylation and trapping of L‐DOPA in most brain regions after IMO. The findings of dye penetration in certain brain regions, which are known to be involved in autonomic regulation, may reflect possible ways of chemical communication between the circulation and neuronal structures in these regions and/or possibly constitute the basis for inactivation processes for transport of substances outwards from the brain as well as potential loci for adverse effects and development of pathological

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb10594.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Plasma glucose, osmolality and insulin have been investigated during hemorrhage in nonstarved rats. The rate of blood loss leading to hemorrhages of 44% and 55% of the estimated original blood volume determined the patterns of response. Substantial hyperglycemic hyperosmolality and insulin values appropriate for the raised levels of glucose were observed in the animals bleeding more rapidly. The slower rate of hemorrhage was associated with only moderate hyperglycemia and hyperosmolality, while the insulin values rose to very high levels, 45 times basal. It is postulated that altered glucose‐insulin metabolism in haemorrhage may have important consequences for fluid homeostasis, and the rate of bleeding is the fundamental factor steering this effec

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb10595.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The effects of L‐DOPA alone and in combination with two inhibitors of I‐aromatic‐amino acid decarboxylase (DC), carbidopa and benserazid on the blood pressure (BP) and catecholamine (CA) content in the heart and brain has been investigated in the lizardAgama caudospinosa. The effect of clonidine on BP has also been examined in intact lizards and after spinal cord transection. It is concluded that dopamine (DA) is formed from L‐DOPA in brain and heart and that carbidopa reduces the DA formation in the heart but penetrates the blood brain barrier (BBB) poorly, allowing a central decarboxylation of L‐DOPA. Benserazid, on the other hand, penetrates the BBB and inhibits the central as well as the peripheral synthesis of DA from L‐DOPA. L‐DOPA in combination with carbidopa lowers the BP significantly in lizards tilted 45°(head upwards) whereas the supine BP is unaffected. Benserazid pretreatment abolishes the decrease in BP after L‐DOPA. L‐DOPA alone does not produce any consistent changes in BP. Clonidine lowers BP in intact, tilted animals, while the BP is increased in spinal animals. The results indicate a central mode of action of L‐DOPA as well as clonidine i

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb10596.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The effects of high repeated subcutaneous doses (4×2 mg/kg) of nicotine have been evaluated on dopamine (DA) and noradrenaline (NA) levels and turnover in the long‐term castrated male rat using catecholamine (CA) fluorescence histochemistry in combination with quantitative microfluorometry. The CA turnover was evaluated by studying the decline of the CA stores following tyrosine hydroxylase inhibition using α‐methyltyrosine methyl ester (H 44/68). In the same experiments trunk blood was collected for the determination of serum prolactin, LH, FSH and TSH levels using standard radioimmun‐oassay procedures. The nicotine treatment produced a significant depletion of CA stores and an increase of CA turnover in DA and NA nerve terminals of the median eminence and in peri‐ and paraventricular NA systems. These effects were significantly counteracted by pretreatment with mecamylamine. Nicotine significantly reduced serum prolactin and TSH levels, and after H 44/68 it also reduced LH and FSH serum levels. These actions were counteracted by mecamylamine pretreatment, except the effects on serum TSH levels after H 44/68, which were even enhanced by pretreatment with mecamylamine. Overall intraindividual correlations showed a significant correlation between reduced CA turnover in several hypothalamic areas and increased serum LH and FSH levels, increased NA turnover in the paraventricular hypothalamic nucleus and increased serum TSH levels, and reduced DA turnover in the median eminence and increased serum LH levels. It is suggested that in the castrated male rat nicotine can activate cholinergic nicotine‐like receptors facilitating DA and NA turnover and release in various hypothalamic CA nerve terminal systems including those inhibiting the secretion of prolactin and LH (DA terminals in medial and lateral palisade zone, respectively) and facilitating secretion of TSH (NA terminals in the parvocellular part of the paraventricular hypothalam

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb10597.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Head‐tail detachment of ejaculated human spermatozoa was studied with phase contrast microscopy. The frequency of head‐tail detachment was assessed after sperm exposure to the anionic detergent sodium dodecyl sulfate (SDS) for 60 min at 22°C. Decapitation was enhanced by EDTA. Zinc reversibly inhibited native as well as EDTA induced head‐tail disconnection. Still a certain proportion of spermatozoa were resistant to EDTA‐treatment and this proportion significantly increased upon 24 h of saline storage. The development of EDTA resistance was enhanced by EDTA treatment before storage. A physiological role for zinc as a preserver of an inherent mechanism for head‐tail detachment is

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb10598.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The effect of hypotensive hemorrhage on plasma vasopressin (AVP) concentration and carotid blood pressure before and after induction of experimental diabetes insipidus (DI) was studied in the conscious goat. Bleeding to the point of blood pressure fall (blood loss 15–25% of the estimated blood volume) caused an immediate, approximately hundred fold, increase in the plasma AVP concentration in the normal animal. Hemorrhage to the same extent during DI did not affect the plasma AVP levels. A rather transient hypotensive response to bleeding was seen before disruption of the pituitary stalk, but during DI the recovery of the hemorrhage‐induced hypotension was less effective. However, the normalization of the blood pressure after bleeding was slightly more efficient during the permanent than during the temporary phase of DI. It is concluded that an intact hypothalamoneurohypophysial connection is necessary for the massive release of AVP normally seen in response to hypotensive hemorrhage. It is also confirmed that the lack of this hormonal response to bleeding is accompanied by an increased susceptibility to the hypotensive effect of hemorrh

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb10599.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The principal zinc binding component in human prostatic fluid and seminal plasma has been found to bind zinc reversible and to be of low molecular weight. Treatment of this zinc containing complex (LMW‐Zn) with trypsin and pronase or acid hydrolysis failed to alter its zinc binding properties or gel chromatographic characteristics. Removal of citrate with a combination of citrate lyase, malate dehydrogenase and lactate dehydrogenase did, however, completely abolish its ability to bind zinc. Spectrographical scanning of LMW‐Zn preparations obtained by gel chromatography of prostatic fluid or seminal plasma on a Sephadex G‐25 column gave identical absorption curves with those obtained by scanning of a zinc‐citrate solution. Application of the same analysis to LMW‐Zn of human breast milk yielded similar results. It is concluded that citrate is the major low molecular weight zinc ligand in prostatic fluid, seminal plasma and br

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1982.tb10600.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY