Increased sensitivity in the interaction of the dopaminergic/adenosinergic system at the level of the adenylate cyclase activity in the striatum of the “weaver” mouse

2016 ◽  
Vol 99 ◽  
pp. 233-238 ◽  
Author(s):  
Botsakis K ◽  
Tondikidou V ◽  
Panagopoulos N ◽  
Margariti M ◽  
Matsokis N ◽  
...  
1979 ◽  
Vol 178 (1) ◽  
pp. 217-221 ◽  
Author(s):  
M D Houslay ◽  
R W Palmer

1. Synthetic lysophosphatidylcholines inhibit the glucagon-stimulated adenylate cyclase activity of rat liver plasma membranes at concentrations two to five times lower than those needed to inhibit the fluoride-stimulated activity. 2. Specific 125I-labelled glucagon binding to hormone receptors is inhibited at concentrations similar to those inhibiting the fluoride-stimulated activity. 3. At concentrations of lysophosphatidylcholines immediately below those causing inhibition, an activation of adenylate cyclase activity or hormone binding was observed. 4 These effects are essentially reversible. 5. We conclude that the increased sensitivity of glucagon-stimulated adenylate cyclase to inhibition may be due to the lysophosphatidylcholines interfering with the physical coupling between the hormone receptor and catalytic unit of adenylate cyclase. 6. We suggest that, in vivo, it is possible that lysophosphatidylcholines may modulate the activity of adenylate cyclase only when it is in the hormone-stimulated state.


1987 ◽  
Vol 116 (2) ◽  
pp. 267-274
Author(s):  
N. Nijs-De Wolf ◽  
J. Corvilain ◽  
P. J. Bergmann

Abstract. We examined the effects of cationized serum albumin on the canine renal membrane adenylate cyclase in the basal state and when stimulated with guanylyl-imidodiphosphate, PTH or NaF. Human albumin was cationized to an isoelectric point greater than 9.5 by the addition of hexamethylene diamine. Cationized albumin increased basal and stimulated cAMP production by the membranes and increased the sensitivity of the system to low doses of PTH (0.25 pmol/l), being usually inactive in buffer alone or in human serum albumin. These observations are comparable to those previously reported on thyroid membranes and cells from adrenal tumours and confirm that positively charged macromolecules can increase adenylate cyclase activity. A decrease in non-specific binding of PTH is only partly responsible for the increased sensitivity to the hormone. Though this increase in sensitivity is small, it could nevertheless be useful in the detection of biologically active PTH after extraction from the serum.


Author(s):  
L.S. Cutler

Many studies previously have shown that the B-adrenergic agonist isoproterenol and the a-adrenergic agonist norepinephrine will stimulate secretion by the adult rat submandibular (SMG) and parotid glands. Recent data from several laboratories indicates that adrenergic agonists bind to specific receptors on the secretory cell surface and stimulate membrane associated adenylate cyclase activity which generates cyclic AMP. The production of cyclic AMP apparently initiates a cascade of events which culminates in exocytosis. During recent studies in our laboratory it was observed that the adenylate cyclase activity in plasma membrane fractions derived from the prenatal and early neonatal rat submandibular gland was retractile to stimulation by isoproterenol but was stimulated by norepinephrine. In addition, in vitro secretion studies indicated that these prenatal and neonatal glands would not secrete peroxidase in response to isoproterenol but would secrete in response to norepinephrine. In contrast to these in vitro observations, it has been shown that the injection of isoproterenol into the living newborn rat results in secretion of peroxidase by the SMG (1).


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