scholarly journals Functional Vasoactive Intestinal Polypeptide (VIP) Receptors in Human Neuroblastoma Subclones That Contain VIP Precursor mRNA and Release VIP-like Substances

1989 ◽  
Vol 264 (7) ◽  
pp. 3647-3650
Author(s):  
J M Muller ◽  
S J Lolait ◽  
V C Yu ◽  
W Sadée ◽  
J A Waschek
Reproduction ◽  
2007 ◽  
Vol 134 (2) ◽  
pp. 281-292 ◽  
Author(s):  
Marzia Barberi ◽  
Barbara Muciaccia ◽  
Maria Beatrice Morelli ◽  
Mario Stefanini ◽  
Sandra Cecconi ◽  
...  

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.


2006 ◽  
Vol 191 (1) ◽  
pp. 287-299 ◽  
Author(s):  
Sergio Vaccari ◽  
Stefania Latini ◽  
Marzia Barberi ◽  
Anna Teti ◽  
Mario Stefanini ◽  
...  

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.


Endocrinology ◽  
2006 ◽  
Vol 147 (5) ◽  
pp. 2197-2202 ◽  
Author(s):  
Lynnette M. Gerhold ◽  
Phyllis M. Wise

Recent studies suggest that astrocytes modulate the GnRH-induced LH surge. In particular, we have shown that the surface area of astrocytes that ensheath GnRH neurons exhibits diurnal rhythms. Vasoactive intestinal polypeptide (VIP) influences numerous aspects of astrocyte function in multiple brain regions and is a neurotransmitter in the suprachiasmatic nucleus (SCN) that affects GnRH neurons. The goals of this study were to: 1) assess whether astrocytes that surround GnRH neurons express VIP receptors, 2) determine the effects VIP suppression in the SCN on the morphometry of astrocytes surrounding GnRH neurons, and 3) assess whether this effect mimics aging-like changes in surface area of astrocytes. Young rats were ovariectomized (d 0), implanted with cannulae into the SCN (d 5), injected with VIP antisense (antioligo) or random sequence oligonucleotides, implanted with capsules containing 17β-estradiol dissolved in oil (d 7), and perfused at 0300, 1400, and 1800 h (d 9). Brains were processed for immunocytochemistry. Our results demonstrate that astrocytes in close apposition to GnRH neurons express VIP receptors. Antioligo treatment blocked diurnal rhythms in surface area of astrocytes ensheathing GnRH neurons. The absence of diurnal rhythms resembles observations in middle-aged rats. Together these findings suggest that the ability of the VIP-containing neurons in the SCN to relay diurnal information to GnRH neurons may be by influencing dynamic changes in the morphometry of astrocytes that surround GnRH neurons. Furthermore, the absence of a VIP rhythm in aging animals may lead to altered GnRH activity via astrocyte-dependent mechanisms.


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