scholarly journals The roles of vasoactive intestinal polypeptide in the mammalian circadian clock

2003 ◽  
Vol 177 (1) ◽  
pp. 7-15 ◽  
Author(s):  
HD Piggins ◽  
DJ Cutler
Keyword(s):  
Circadian Clock ◽  
Vasoactive Intestinal Polypeptide ◽  
Chemical Constituents ◽  
Neural Pathways ◽  
Circadian Pacemaker ◽  
Suprachiasmatic Nuclei ◽  
Environmental Signals ◽  
Intestinal Polypeptide

Biological oscillations with an endogenous period of near 24 h (circadian rhythms) are generated by the master circadian pacemaker or clock located in the suprachiasmatic nuclei (SCN) of the hypothalamus. This clock is synchronised to recurring environmental signals conveyed by selective neural pathways. One of the main chemical constituents of SCN neurones is vasoactive intestinal polypeptide (VIP). Such neurones are retinorecipient and activated by light. Exogenous application of VIP resets the SCN circadian clock in a light-like manner, both in vivo and in vitro. These resetting actions appear to be mediated through the VPAC2 receptor (a type of receptor for VIP). Unexpectedly, genetically ablating expression of the VPAC2 receptor renders the circadian clock arrhythmic at the molecular, neurophysiological and behavioural levels. These findings indicate that this intrinsic neuropeptide acting through the VPAC2 receptor participates in both resetting to light and maintenance of ongoing rhythmicity of the SCN.

scholarly journals Participation of vasoactive intestinal polypeptide in ovarian steroids production during the rat estrous cycle and in the development of estradiol valerate-induced polycystic ovary

Reproduction ◽  
2007 ◽  
Vol 133 (1) ◽  
pp. 147-154 ◽  
Author(s):  
Claudio Parra ◽  
Jenny L Fiedler ◽  
S Leticia Luna ◽  
Monika Greiner ◽  
Vasantha Padmanabhan ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Vasoactive Intestinal Polypeptide ◽  
Polycystic Ovary ◽  
Secretory Activity ◽  
Estradiol Valerate ◽  
Steroid Secretion ◽  
Cyclic Changes ◽  
Intestinal Polypeptide

Vasoactive intestinal polypeptide (VIP) stimulates estradiol and progesterone release from ovarian granulosa cells in vitro. Very little information is available as to the role VIP plays in the control of steroid secretion during reproductive cyclicity and in ovarian pathologies involving altered steroid secretion. In this study, we determined the involvement of VIP in regulating ovarian androgen and estradiol release during estrous cyclicity and estradiol valerate (EV)-induced polycystic ovarian development in rats. Our findings show that androgen and estradiol release from ovaries obtained during different stages of rat estrous cycle mimic cyclic changes in steroid release observed in vivo with maximal release occurring during late proestrus. VIP increased androgen release from ovaries of all cycle stages except late proestrus and estradiol release from all cycle stages. Increases in VIP-induced androgen and estradiol release were maximal at early proestrus. Inclusion of saturating concentrations of androstenedione increased magnitude of VIP-induced estradiol release at diestrus and estrus but not proestrus. Magnitude of VIP-induced androgen and estradiol release tended to be greater in the ovaries from EV-treated rats with polycystic ovary compared with estrous controls. At the tissue level, ovarian VIP concentration was cycle stage dependent with highest level seen in diestrus. Maximum concentration of VIP was found in EV-treated rats. Changes in VIP were inversely related to changes in ovarian nerve growth factor, a neuropeptide involved in ovarian androgen secretion. These results strongly suggest that intraovarian VIP participates in the control of estradiol secretion during the rat estrous cycle and possibly in the maintenance of increased ovarian estradiol secretory activity of EV-treated rats.

Effects of Vasoactive Intestinal Polypeptide on Neurones of the Rat Suprachiasmatic Nuclei In Vitro

2002 ◽  
Vol 14 (8) ◽  
pp. 639-646 ◽  
Author(s):  
H. E. Reed ◽  
D. J. Cutler ◽  
T. M. Brown ◽  
J. Brown ◽  
C. W. Coen ◽  
...  
Keyword(s):  
Vasoactive Intestinal Polypeptide ◽  
Suprachiasmatic Nuclei ◽  
Intestinal Polypeptide

A common trans-acting factor is involved in transcriptional regulation of neurotransmitter genes by cyclic AMP

1988 ◽  
Vol 8 (10) ◽  
pp. 4225-4233
Author(s):  
S E Hyman ◽  
M Comb ◽  
Y S Lin ◽  
J Pearlberg ◽  
M R Green ◽  
...  
Keyword(s):  
Tyrosine Hydroxylase ◽  
Cyclic Amp ◽  
Vasoactive Intestinal Polypeptide ◽  
Transcriptional Activation ◽  
Second Messengers ◽  
Regulation Of Transcription ◽  
Neurotransmitter Genes ◽  
Intestinal Polypeptide

Activation of neurotransmitter receptors can regulate transcription in postsynaptic cells through the actions of second messengers. Trans-synaptic regulation of transcription appears to be an important mechanism controlling the synthesis of molecules involved in neuronal signaling, especially neuropeptides. Proenkephalin, vasoactive intestinal polypeptide, and somatostatin have been shown to be transcriptionally regulated by the second messenger, cyclic AMP (cAMP), as has the catecholamine synthesizing enzyme tryosine hydroxylase. cAMP-inducible elements have been mapped within these genes, and trans-acting factors which bind to several such elements have been identified. With the discovery that individual neurons generally contain multiple transmitters within their synaptic terminals, it has become important to understand in detail the mechanisms by which the synthesis of transmitters can be coregulated. Here we compare the structure and function of the proenkephalin cAMP-inducible enhancer with the mapped cAMP-inducible elements of the vasoactive intestinal polypeptide, somatostatin, and tyrosine hydroxylase genes and a putative cAMP-inducible element in the proto-oncogene c-fos. We have previously shown that the proenkephalin enhancer is composed of two different elements, ENKCRE-1 and ENKCRE-2. We show here that one of these, ENKCRE-2, is structurally similar to elements found within the vasoactive intestinal polypeptide, somatostatin, and tyrosine hydroxylase genes and binds a trans-acting factor that is competed for both in cotransfection experiments (in vivo) and in DNase I footprint assays (in vitro) by these other elements. The c-fos element has similar structural requirements to confer transcriptional induction by cAMP but competes less strongly. Protein purified by affinity chromatography with the ENKCRE-2 sequence binds to each of these elements. A second element within the proenkephalin cAMP-inducible enhancer, ENKCRE-1, binds a factor that is not competed for by these other genes and is therefore distinct. This analysis suggests a potential mechanism of transcriptional coregulation of the neuronally expressed genes investigated in this study and also demonstrates that multiple factors are involved in transcriptional activation by cAMP.

scholarly journals A common trans-acting factor is involved in transcriptional regulation of neurotransmitter genes by cyclic AMP.

1988 ◽  
Vol 8 (10) ◽  
pp. 4225-4233 ◽  
Author(s):  
S E Hyman ◽  
M Comb ◽  
Y S Lin ◽  
J Pearlberg ◽  
M R Green ◽  
...  
Keyword(s):  
Tyrosine Hydroxylase ◽  
Cyclic Amp ◽  
Vasoactive Intestinal Polypeptide ◽  
Transcriptional Activation ◽  
Second Messengers ◽  
Regulation Of Transcription ◽  
Neurotransmitter Genes ◽  
Intestinal Polypeptide

Activation of neurotransmitter receptors can regulate transcription in postsynaptic cells through the actions of second messengers. Trans-synaptic regulation of transcription appears to be an important mechanism controlling the synthesis of molecules involved in neuronal signaling, especially neuropeptides. Proenkephalin, vasoactive intestinal polypeptide, and somatostatin have been shown to be transcriptionally regulated by the second messenger, cyclic AMP (cAMP), as has the catecholamine synthesizing enzyme tryosine hydroxylase. cAMP-inducible elements have been mapped within these genes, and trans-acting factors which bind to several such elements have been identified. With the discovery that individual neurons generally contain multiple transmitters within their synaptic terminals, it has become important to understand in detail the mechanisms by which the synthesis of transmitters can be coregulated. Here we compare the structure and function of the proenkephalin cAMP-inducible enhancer with the mapped cAMP-inducible elements of the vasoactive intestinal polypeptide, somatostatin, and tyrosine hydroxylase genes and a putative cAMP-inducible element in the proto-oncogene c-fos. We have previously shown that the proenkephalin enhancer is composed of two different elements, ENKCRE-1 and ENKCRE-2. We show here that one of these, ENKCRE-2, is structurally similar to elements found within the vasoactive intestinal polypeptide, somatostatin, and tyrosine hydroxylase genes and binds a trans-acting factor that is competed for both in cotransfection experiments (in vivo) and in DNase I footprint assays (in vitro) by these other elements. The c-fos element has similar structural requirements to confer transcriptional induction by cAMP but competes less strongly. Protein purified by affinity chromatography with the ENKCRE-2 sequence binds to each of these elements. A second element within the proenkephalin cAMP-inducible enhancer, ENKCRE-1, binds a factor that is not competed for by these other genes and is therefore distinct. This analysis suggests a potential mechanism of transcriptional coregulation of the neuronally expressed genes investigated in this study and also demonstrates that multiple factors are involved in transcriptional activation by cAMP.

Vasoactive intestinal polypeptide excites mammalian dorsal horn neurons both in vivo and in vitro

1982 ◽  
Vol 243 (1) ◽  
pp. 158-164 ◽  
Author(s):  
Srdija Jeftinija ◽  
Kazuyuki Murase ◽  
Vladimir Nedeljkov ◽  
Mirjana Randic
Keyword(s):  
Dorsal Horn ◽  
Vasoactive Intestinal Polypeptide ◽  
Dorsal Horn Neurons ◽  
Intestinal Polypeptide

scholarly journals Disrupted Neuronal Activity Rhythms in the Suprachiasmatic Nuclei of Vasoactive Intestinal Polypeptide-Deficient Mice

2007 ◽  
Vol 97 (3) ◽  
pp. 2553-2558 ◽  
Author(s):  
T. M. Brown ◽  
C. S. Colwell ◽  
J. A. Waschek ◽  
H. D. Piggins
Keyword(s):  
Vasoactive Intestinal Polypeptide ◽  
Wheel Running ◽  
Brain Slices ◽  
Suprachiasmatic Nuclei ◽  
Wild Type ◽  
Behavioral Rhythms ◽  
Adult Mice ◽  
Deficient Mice ◽  
Intestinal Polypeptide

Vasoactive intestinal polypeptide (VIP), acting via the VPAC2 receptor, is a key signaling pathway in the suprachiasmatic nuclei (SCN), the master clock controlling daily rhythms in mammals. Most mice lacking functional VPAC2 receptors are unable to sustain behavioral rhythms and lack detectable SCN electrical rhythms in vitro. Adult mice that do not produce VIP (VIP/PHI−/−) exhibit less severe alterations in wheel-running rhythms, but the effects of this deficiency on the amplitude, phasing, or periodicity of their SCN cellular rhythms are unknown. To investigate this, we used suction electrodes to extracellularly record multiple- and single-unit electrical activity in SCN brain slices from mice with varying degrees of VIP deficiency, ranging from wild-type (VIP/PHI+/+) to heterozygous (VIP/PHI+/−) and VIP/PHI−/− animals. We found decreasing proportions of rhythmic cells in SCN slices from VIP/PHI+/+ (∼91%, n = 23) through VIP/PHI-/+ (∼71%, n = 28) to VIP/PHI−/− mice (62%; n = 37) and a parallel trend toward decreasing amplitude in the remaining rhythmic cells. SCN neurons from VIP/PHI−/− mice exhibited a broad range in the period and phasing of electrical rhythms, concordant with the known alterations in their behavioral rhythms. Further, treatment of VIP/PHI−/− slices with a VPAC2 receptor antagonist significantly reduced the proportion of oscillating neurons, suggesting that VPAC2 receptors still become activated in the SCN of these mice. The results establish that VIP is important for appropriate periodicity and phasing of SCN neuronal rhythms and suggest that residual VPAC2 receptor signaling promotes rhythmicity in adult VIP/PHI−/− mice.

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