Effects of pituitary adenylate cyclase-activating polypeptide and vasoactive intestinal polypeptide on cyclic AMP accumulation in sheep pituitary cells in vitro

1996 ◽  
Vol 148 (3) ◽  
pp. 545-552 ◽  
Author(s):  
K Sawangjaroen ◽  
C Sernia ◽  
J D Curlewis
Keyword(s):  
Adenylate Cyclase ◽  
Vasoactive Intestinal Polypeptide ◽  
Rapid Development ◽  
Intracellular Camp ◽  
Type I ◽  
Pituitary Cells ◽  
Camp Accumulation ◽  
Pituitary Adenylate Cyclase ◽  
Camp Levels ◽  
Intestinal Polypeptide

Abstract Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) are known to stimulate adenylate cyclase activity in rat pituitary cells but no direct effects have been reported on sheep pituitary cells. In this study we determined whether either peptide could stimulate intracellular cAMP accumulation in dispersed sheep pituitary cells in primary culture. Time course studies with PACAP showed that tachyphylaxis developed rapidly and so a short incubation time (5 min) was used to define the dose–response relationship. PACAP dose-dependently stimulated intracellular cAMP levels with a half-maximum response at 2·9 ± 0·2 nmol/l (n=4). In contrast, VIP only caused a small increase in intracellular cAMP levels at the highest dose tested (1 μmol/l). The VIP antagonist [4C1-d-Phe6,Leu17]VIP had no effect on the cAMP response to either PACAP or VIP while the peptide PACAP(6–38), a putative PACAP antagonist, blocked the cAMP response to PACAP. The desensitisation to PACAP was further investigated by pretreating cells with PACAP for 30 min. After a further 15 min in culture medium alone, these cells showed no cAMP response to subsequent treatment with PACAP but could respond to forskolin. When a longer incubation period of 240 min was used between the first and second treatment with PACAP, a partial return in responsiveness to PACAP was observed. In summary, these results show that PACAP activates adenylate cyclase in sheep pituitary cells but that there is rapid development of tachyphylaxis. Experiments with the antagonists suggest that the response to PACAP is via the PACAP type I receptor. In contrast, physiological doses of VIP do not stimulate cAMP accumulation in sheep pituitary cells. Journal of Endocrinology (1996) 148, 545–552

scholarly journals Expression localisation and functional activity of pituitary adenylate cyclase-activating polypeptide, vasoactive intestinal polypeptide and their receptors in mouse ovary

Reproduction ◽  
2007 ◽  
Vol 134 (2) ◽  
pp. 281-292 ◽  
Author(s):  
Marzia Barberi ◽  
Barbara Muciaccia ◽  
Maria Beatrice Morelli ◽  
Mario Stefanini ◽  
Sandra Cecconi ◽  
...  
Keyword(s):  
Adenylate Cyclase ◽  
Vasoactive Intestinal Polypeptide ◽  
Granulosa Cells ◽  
Ovarian Tissue ◽  
Type I ◽  
Mouse Ovary ◽  
Vip Receptors ◽  
Pituitary Adenylate Cyclase ◽  
Preovulatory Follicles ◽  
Intestinal Polypeptide

Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) positively affect several parameters correlated with the ovulatory process. PACAP is transiently expressed in rat preovulatory follicles, while VIP is present in nerve fibres at all stages of development. These two peptides act by interacting with three types of receptors: PACAP type I receptor (PAC1-R), which binds with higher affinity to PACAP, and two VIP receptors (VPAC1-R and VPAC2-R), which bind to PACAP and VIP with equal affinity. The aim of the present study was to characterise the PACAP/VIP/receptor system in the mouse ovary. Results obtained by RT-PCR, immunohistochemistry and in situ hybridisation showed that PACAP was transiently expressed in granulosa cells of preovulatory follicles after human chorionic gonadotrophin (hCG) stimulation, while VIP mRNA was never observed. All the receptors were present in 22-day-old untreated mice. In preovulatory follicles, PAC1-R was expressed both in granulosa cells and in residual ovarian tissue but was stimulated by hCG mainly in granulosa cells; VPAC2-R was present in both the cell compartments and was only mildly stimulated; VPAC1-R was present mainly in the residual ovarian tissue and was downregulated by hCG. PACAP and VIP were equipotent in inhibiting apoptosis in granulosa cells, confirming the presence of functional PACAP/VIP receptors. The contemporary induction by hCG of PACAP and PAC1-R in granulosa cells of preovulatory follicles suggests that, also in mouse ovary, PACAP may play a significant role around the time of ovulation. Moreover, the presence of PACAP/VIP receptors in the untreated ovary suggests a possible role for PACAP and VIP during follicle development.

scholarly journals Characterization and expression of different pituitary adenylate cyclase-activating polypeptide/vasoactive intestinal polypeptide receptors in rat ovarian follicles

2006 ◽  
Vol 191 (1) ◽  
pp. 287-299 ◽  
Author(s):  
Sergio Vaccari ◽  
Stefania Latini ◽  
Marzia Barberi ◽  
Anna Teti ◽  
Mario Stefanini ◽  
...  
Keyword(s):  
Adenylate Cyclase ◽  
Vasoactive Intestinal Polypeptide ◽  
Granulosa Cells ◽  
Type I ◽  
Vip Receptors ◽  
Pituitary Adenylate Cyclase ◽  
Preovulatory Follicles ◽  
Stimulation Of ◽  
Whole Ovaries ◽  
Intestinal Polypeptide

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a bioactive peptide transiently expressed in preovulatory follicles. PACAP acts by interacting with three types of PACAP receptors. PACAP type I receptor (PAC1-R), which binds specifically to both PACAPs and vasoactive intestinal polypeptide (VIP), although with lower affinity, and two VIP receptors, VPAC1-R and VPAC2-R, which bind to PACAP and VIP with equal affinity. In the present study, we showed the expression of all three receptors in whole ovaries obtained from juvenile and gonadotropin-treated immature rats. A more detailed analysis on cells from preovulatory follicles showed that PAC1-R and VPAC2-R were expressed in granulosa cells, whereas only VIP receptors were expressed in theca/interstitial (TI) cells and fully grown oocytes presented only PAC1-R. The distribution of the VIP receptors was confirmed by immunofluorescence. HCG treatment induced stimulation of PAC1-R in granulosa cells and VPAC2-R in TI cells. The presence of functional PACAP/VIP receptors was also supported by metabolic studies. We further evaluated the presence of PACAP and VIP receptors by testing the effect of these peptides on apoptosis in granulosa cells cultured, isolated or in whole follicles. Treatment of follicles with PACAP and VIP dose-dependently inhibited apoptosis, while only PACAP significantly inhibited isolated granulosa cells. These results demonstrate a different expression of PACAP/VIP receptors in the various follicle compartments and suggest a possible role for PACAP and VIP on granulosa and TI cells, both during follicle development and ovulation.

Phospholipids stabilize binding of pituitary adenylate cyclase-activating peptide to vasoactive intestinal polypeptide receptor

2021 ◽  
Author(s):  
Nidhin Thomas ◽  
Ashutosh Agrawal
Keyword(s):  
Adenylate Cyclase ◽  
Receptor Binding ◽  
Vasoactive Intestinal Polypeptide ◽  
Binding Free Energy ◽  
Active Role ◽  
Lipid Binding ◽  
Peripheral Tissues ◽  
Peptide Receptor ◽  
Pituitary Adenylate Cyclase ◽  
Intestinal Polypeptide

Vasoactive intestinal polypeptide receptor (VIP1R) is a class B G-protein coupled receptor (GPCR) that is widely distributed throughout the central nervous system, T-lymphocytes, and peripheral tissues of organs like lungs and liver. Critical functions of these receptors render them potential pharmacological targets for the treatment of a broad spectrum of inflammatory and neurodegenerative diseases. Here we use atomistic studies to show that phospholipids can act as potent regulators of peptide binding on to the receptor. We simulated the binding of neuropeptide pituitary adenylate cyclase-activating peptide (PACAP27) into the transmembrane bundle of the receptor. The simulations reveal two lipid binding sites on the peptidic ligand for the negatively charged phosphodiester of phospholipids in the extracellular leaflet which lower the peptide-receptor binding free energy by ~8kBT. We further simulated the effect of anionic lipids phosphatidylinositol-4,5-bisphosphate (PIP2). These lipids show much stronger interaction, lowering the peptide-receptor binding energy by an additional ~7kBT compared to POPC lipids. These findings suggest that lipids can play an active role in catalyzing peptide-receptor binding and activating vasoactive intestinal polypeptide receptors.

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