scholarly journals Stimulation of hippocampal adenylyl cyclase activity dissociates memory consolidation processes for response and place learning

2006 ◽  
Vol 13 (3) ◽  
pp. 342-348 ◽  
Author(s):  
G. Martel
1999 ◽  
Vol 128 (1) ◽  
pp. 158-164 ◽  
Author(s):  
David R Thomas ◽  
Derek N Middlemiss ◽  
Stephen G Taylor ◽  
Paul Nelson ◽  
Anthony M Brown

1997 ◽  
Vol 273 (6) ◽  
pp. F883-F891 ◽  
Author(s):  
Mark D. Okusa ◽  
Liping Huang ◽  
Akemi Momose-Hotokezaka ◽  
Long P. Huynh ◽  
Amy J. Mangrum

We employed two guanine nucleotide binding protein (G protein)-coupled receptors known to be targeted to opposite domains in renal epithelial cells to test the hypothesis that the polarized receptor expression of receptors regulates the activity of the receptor’s effector molecule, adenylyl cyclase. We used LLC-PK1 cells stably transfected with cDNA encoding the α2B-adrenergic receptor (α2B-AR) or A1-adenosine receptor (A1-AdR). Immunohistochemistry and Western blot analysis confirmed the basolateral and apical expression of α2B-ARs and A1-AdRs, respectively. Adenylyl cyclase activity was assessed by measuring cAMP accumulation following the addition of forskolin (10 μM) in the presence of 3-isobutyl-1-methylxanthine to apical or basolateral chambers of confluent monolayers. A five- to sixfold increase in cAMP accumulation occurred following apical (or basolateral) stimulation of LLC-PK1 cells expressing apical (or basolateral) receptors in comparison to forskolin stimulation of corresponding domains of untransfected cells. We conclude 1) adenylyl cyclase activity is present at or near the apical and basolateral domains of LLC-PK1 cells, and 2) factors that regulate the polarized expression of inhibitory G protein-coupled receptors may also regulate local adenylyl cyclase activity.


1993 ◽  
Vol 13 (2) ◽  
pp. 69-77 ◽  
Author(s):  
A. M. Bajo ◽  
L. G. Guijarro ◽  
M. G. Juarranz ◽  
P. Valenzuela ◽  
P. Martinez ◽  
...  

Vasoactive intestinal peptide (VIP) has been shown to stimulate adenylyl cyclase activity in human endometrial membranes. The effect was dependent on the time and temperature of incubation as well as on the concentration of endometrial membrane proteins in the medium. In the presence of 1 μM GTP, half-maximal stimulation of adenylyl cyclase activity was observed at 25.0 ± 7.0 nM VIP, whereas the maximal activity (at 1 μM VIP)corresponded to an increase of about 140% with respect to basal values (7.5 ± 0.6 pmol cyclic AMP/min/mg of protein). However, the maximal stimulation of adenylyl cyclase activity was obtained with helodermin (1 μM) that increased the activity by 170% over the basal. The relative potency of VIP-related peptides upon the adenylyl cyclase activity was: helodermin (ED50 = 1.8 ± 1.4 nM) > VIP(ED50 = 25.0 ± 7.0 nM) > PHI (ED50 = 725.0 ± 127.2 nM). Secretin had a faint effect upon the adenylyl cyclase activity and glucagon was completely inefficient at this level. The presence of αs and αi subunits of G proteins in human endometrium was detected by immunoblot. Preliminary results showed the presence of two classes of 125I-VIP receptors in human endometrial membranes with the following stoichoimetric parameters: high affinity receptor (Kd=2.0 nM, binding capacity 0.1 pmol VIP/mg protein) and low affinity receptor (Kd = 0.43 μM, binding capacity 13.1 pmol VIP/mg protein). The present results together with the known presence of VIP in human uterus and the actions of this neuropeptide in the adjacent myometrial tissue support the idea that VIP and related peptides may have a role in human endometrium.


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