首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 578 毫秒
1.
R K Dismukes  J W Daly 《Experientia》1976,32(6):730-732
The accumulation of radioactive cyclic AMP elicited by various neurohormones has been examined in adenine-labeled telencephalon slices from rats raised in enriched or impoverished environments. Basal levels of cyclic AMP and responses of the brain slice cyclic AMP-generating systems to norepinephrine, isoproterenol and adenosine did not differ between the two group of rats, while responses to prostaglandin E1 were significantly greater with the impoverished group and responses to histamine appeared to be greater with the enriched group.  相似文献   

2.
Summary Alrestatin at 25–1×10–4 M inhibited the accumulation of cyclic AMP induced by prostaglandin E2, but not theophylline, in the rat anterior pituitary in vitro. Somatostatin, at lower concentrations, inhibited both; maximal inhibition of the prostaglandin effect was greater with alrestatin. As cyclic AMP is considered to be a mediator in induced-hormonal release, it appears from the present findings that alrestatin may be of potential use in altering hormonal release.The author acknowledges the technical assistance of Miss C. Pilapil.  相似文献   

3.
Summary Reliability of measurement of lymphocyte cyclic AMP synthesis in intact cells was estimated by taking 3 successive blood samples during a one-month period from 11 healthy volunteers. Isoproterenol and prostaglandin E1-stimulated cyclic AMP accumulation were used to evaluate the activity of these two receptor activities in human lymphocytes. Forskolin-stimulated cyclic AMP accumulation was used to evaluate the activity of the Ns/catalytic subunit. Only for forskolin was significant reliability observed. For isoproterenol and prostaglandin E1 significant reliability was observed only for male subjects.Acknowledgment. This work was supported in part by the following organizations: Chief Scientist's Office, Israel Ministry of Health; Herman Goldman Foundation, New York; United Jewish Endowment Fund of Greater Washington-Pollinger Foundation.  相似文献   

4.
Summary Isolated rat hearts were subjected to hypoxic perfusion on a recirculating Langendorff apparatus. Following a 30-min-period of aerobic stabilization the hearts were perfused for 30 min with media equilibrated with 84% N2, 12% O2 and 4% CO2. At the end of the hypoxic period myocardial concentrations of cyclic AMP and cyclic GMP were determined by radioimmunoassay. Exposure to hypoxia resulted in a significant increase in cyclic AMP (p<0.01) and a decrease in cyclic GMP (p<0.05) as compared to hearts perfused for 60 min with media gassed with 96% O2, 4% CO2.Acknowledgment. We gratefully acknowledge the excellent technical assistance provided by Mrs Inger O. Boggs and Miss Patricia C. Hannigan. This work was supported in part by U. S. Public Health Service grant HL 14661 from the National Heart and Lung Institute, and by a grant from the Central Ohio Heart Chapter.  相似文献   

5.
Summary To investigate the roles of adenosine A1 and A2 receptors in the regulation of aldosterone production, we examined the effects of adenosine and adenosine agonists (N6-cyclohexyl adenosine; selective adenosine A1 receptor agonist and 5-N-ethylcarboxamine adenosine; selective adenosine A2 receptor agonist) on aldosterone and cyclic AMP production in rat adrenal capsular cells. Neither adenosine nor 5-N-ethylcarboxamine adenosine caused significant effects on basal aldosterone or cyclic AMP production. Also, adenosine (10–3M) showed no consistent effects on aldosterone and cyclic AMP production induced by ACTH. On the other hand, N6-cyclohexyl adenosine exhibited a significant inhibition of basal aldosterone and cyclic AMP production at doses of 10–4 M and 10–3 M; furthermore, 10–3 M N6-cyclohexyl adenosine inhibited aldosterone and cyclic AMP production stimulated by ACTH. These results suggest that adenosine A1 receptors are coupled to and inhibit adenylate cyclase and may be involved in the inhibition of aldosterone production.  相似文献   

6.
Summary Prostaglandins (PGE1) and dibutyryl cyclic AMP (dBc AMP) induce similar morphological changes in astrocytes obtained in primary cultures. PGE1 and dBc AMP increased 2 enzymes of GABA and glutamate metabolism, GABA-T and AAT, but did not modify GDH and GLN-S. Prostaglandins probably affect the cAMP content of glial cells and act in the same way as dBc AMP on glial cell differentiation.  相似文献   

7.
Tissue content of cyclic AMP was as much as 10 times greater in ganglioneuroma than in neuroblastoma. This high cyclic AMP in ganglioneuroma was not significantly different from that of sympathetic ganglia.  相似文献   

8.
D A Taylor  T W Stone 《Experientia》1978,34(4):481-482
At low doses, theophylline blocks the neuronal depressant effects of 5'-AMP, but not cyclic AMP. Higher doses (100 mg/kg) block cyclic AMP responses and reduce the effects of noradrenaline and GABA. It is concluded that cyclic AMP does not depress neurones via the adenosine receptor.  相似文献   

9.
Summary At low doses, theophylline blocks the neuronal depressant effects of 5-AMP, but not cyclic AMP. Higher doses (100 mg/kg) block cyclic AMP responses and reduce the effects of noradrenaline and GABA. It is concluded that cyclic AMP does not depress neurones via the adenosine receptor.We are grateful to the Wellcome Trust and Royal Society for travel grants.  相似文献   

10.
Summary Tissue content of cyclic AMP was as much as 10 times greater in ganglioneuroma than in neuroblastoma. This high cyclic AMP in ganglioneuroma was not significantly different from that of sympathetic ganglia.  相似文献   

11.
W Lippmann 《Experientia》1978,34(4):441-443
Alrestatin at 25-1 X 10(-4) M inhibited the accumulation of cyclic AMP induced by prostaglandin E2, but not theophylline, in the rat anterior pituitary in vitro. Somatostatin, at lower concentrations, inhibited both; maximal inhibition of the prostaglandin effect was greater with alrestatin. As cyclic AMP is considered to be a mediator in induced-hormonal release, it appears from the present findings that alrestatin may be of potential use in altering hormonal release.  相似文献   

12.
The existence of a circadian variation in the adrenocortical concentrations of cyclic AMP and cyclic GMP in male adult Wistar rats examined 10 days after hypophysectomy is demonstrated. The results suggest that the circadian variations of adrenocortical cyclic nucleotides observed previously in intact rats might not entirely depend upon pituitary corticotrophin.  相似文献   

13.
Summary The existence of a circadian variation in the adrenocortical concentrations of cyclic AMP and cyclic GMP in male adult Wistar rats examined 10 days after hypophysectomy is demonstrated. The results suggest that the circadian variations of adrenocortical cyclic nucleotides observed previously in intact rats might not entirely depend upon pituitary corticotrophin.Acknowledgment. Thanks are due to Prof. J. M. Racadot and Dr Y. Drouet for their assistance with the histological examinations.  相似文献   

14.
Receptors for the Vasoactive Intestinal Peptide (VIP) were characterized in particles enriched in plasma membranes obtained from a human prolactin-secreting pituiatry tumor. Native VIP inhibited competitively the binding of 125I-VIP to the particles and stimulated cyclic AMP production; both these effects were observed at concentrations of VIP as low as 10(-11)-10(-10) M, which are compatible with VIP concentrations in the hypothalamopituitary portal blood.  相似文献   

15.
Summary Beta-adrenergic-associated cyclic AMP accumulation was studied in intact lymphocytes before and after transformation with Epstein-Barr virus into immortal cell lines. Although a marked reduction in isoproterenol-stimulated cyclic AMP synthesis was observed in transformed cells, forskolin-stimulated cyclic AMP accumulation was preserved. A parallel loss of125-iodocyanopindolol binding sites suggests that the reduction in beta-adrenergic-stimulated AMP synthesis is due to receptor down regulation.  相似文献   

16.
Summary Prostaglandin E1 noncompetitively inhibits 5-hydroxytryptamine- and theophylline-stimulated cyclic AMP production in the salivary glands of Calliphora erythrocephala by an inhibitory effect on adenyl cyclase. Phosphodiesterase is not affected.  相似文献   

17.
Summary Application of GA3 and cyclic AMP to cowpea seedlings caused a 2–3 fold stimulation of RNAase activity, together with the augmentation of RNAase isoenzymes. Inhibitor studies indicated the requirement of fresh RNA and protein synthesis for enzyme stimulation.  相似文献   

18.
Calcitonin release from 6.23 rat medullary thyroid carcinoma C-cells was stimulated by dibutyryl cyclic AMP and inhibited by dibutyryl cyclic GMP in concentration dependent fashion. Histamine, isoproterenol, prostaglandin E2 and Bay K 8644 stimulated calcitonin release, while acetylcholine and serotonin had no significant effect on CT release.  相似文献   

19.
C P Chow  H H Cornish 《Experientia》1979,35(8):1090-1091
This study suggests that replacement of intracellular potassium by rubidium ions might lower the resting membrane potential. Thus rubidium-treated rats were more responsive to depolarizing influences and generated more cyclic AMP in the brainstem and consequently the behavioral changes.  相似文献   

20.
Summary This study suggests that replacement of intracellular potassium by rubidium ions might lower the resting membrane potential. Thus rubidium-treated rats were more responsive to depolarizing influences and generated more cyclic AMP in the brainstem and consequently the behavioral changes.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号