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Central cholinergic signal-mediated neuroendocrine regulation of vasopressin and oxytocin in ovine fetuses.

Shi L, Mao C, Zeng F, Zhang Y, Xu Z - BMC Dev. Biol. (2008)

Bottom Line: I.c.v. carbachol significantly increased fetal plasma AVP and OT concentrations.The results indicate that the central cholinergic mechanism is established and functional in the regulation of the hypothalamic neuropeptides during the final trimester of pregnancy.This provides evidence for a functional link between the development of central cholinergic mechanisms and hypothalamic neuropeptide systems in the fetus.

View Article: PubMed Central - HTML - PubMed

Affiliation: Perinatal Biology Center, Soochow University School of Medicine, Suzhou 215007, PR China. lshi@llu.edu

ABSTRACT

Background: The hypothalamic-neurohypophysial system plays a fundamental role in the maintenance of body fluid homeostasis by secreting arginine vasopressin (AVP) and oxytocin (OT) in response to a variety of signals, including osmotic and nonosmotic stimuli. It is well established that central cholinergic mechanisms are critical in the regulation of cardiovascular responses and maintenance of body fluid homeostasis in adults. Our recent study demonstrated that intracerebroventricular (i.c.v.) injection of carbachol elicited an increase of blood pressure in the near-term ovine fetuses. However, in utero development of brain cholinergic mechanisms in the regulation of the hypothalamic neuropeptides is largely unknown. This study investigated AVP and OT neural activation in the fetal hypothalamus induced by central carbachol.

Results: Chronically prepared near-term ovine fetuses (0.9 gestation) received an i.c.v. carbachol (3 microg/kg). Fetal blood samples were collected for AVP and OT assay, and brains were used for c-fos mapping studies. I.c.v. carbachol significantly increased fetal plasma AVP and OT concentrations. Intense FOS immunoreactivity (FOS-ir) was observed in the fetal supraoptic nuclei (SON) and paraventricular nuclei (PVN) in the hypothalamus. Double labeling demonstrated that a number of AVP- and OT-containing neurons in the fetal SON and PVN were expressing c-fos in response to central carbachol.

Conclusion: The results indicate that the central cholinergic mechanism is established and functional in the regulation of the hypothalamic neuropeptides during the final trimester of pregnancy. This provides evidence for a functional link between the development of central cholinergic mechanisms and hypothalamic neuropeptide systems in the fetus.

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The effect of i.c.v. carbachol on fetal (A) and maternal (B) plasma OT concentration. The dose of carbachol, 3 μg/kg; 0 min: time for i.c.v. injection. *, P < 0.01 compared with the baseline level. OT: oxytocin.
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Figure 2: The effect of i.c.v. carbachol on fetal (A) and maternal (B) plasma OT concentration. The dose of carbachol, 3 μg/kg; 0 min: time for i.c.v. injection. *, P < 0.01 compared with the baseline level. OT: oxytocin.

Mentions: There was no significant difference in plasma AVP and OT levels between the control and the experimental ewes to i.c.v. injection (AVP: F8,1 = 0.37, OT: F8,1 = 0.23, both P > 0.05). However, the fetal AVP and OT concentrations were significantly increased after i.c.v. carbachol administration (AVP: F8,1 = 73.60, OT: F8,1 = 58.61, P < 0.01). In the control group, i.c.v. injection of the vehicle did not change the maternal and fetal plasma AVP or OT levels. The i.c.v. carbachol significantly increased fetal plasma AVP and OT levels (AVP: F28,6 = 43.23; OT: F28,6 = 35.40, respectively, both P < 0.01, the baseline period vs the period after i.c.v. injection) (Figure 1 and 2). Fetal plasma AVP and OT increased significantly within 15 minutes after i.c.v. carbachol, and the peak levels of plasma AVP and OT were observed at 30 minutes (AVP: from base line level 3.5 ± 1.2 to 53.4 ± 9.5 pg/ml; OT: from base line level 35.6 ± 6.0 to 228.3 ± 23.2 pg/ml) after injection of carbachol. There was no change in maternal plasma AVP and OT after i.c.v. injection of carbachol into the fetus.


Central cholinergic signal-mediated neuroendocrine regulation of vasopressin and oxytocin in ovine fetuses.

Shi L, Mao C, Zeng F, Zhang Y, Xu Z - BMC Dev. Biol. (2008)

The effect of i.c.v. carbachol on fetal (A) and maternal (B) plasma OT concentration. The dose of carbachol, 3 μg/kg; 0 min: time for i.c.v. injection. *, P < 0.01 compared with the baseline level. OT: oxytocin.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2570685&req=5

Figure 2: The effect of i.c.v. carbachol on fetal (A) and maternal (B) plasma OT concentration. The dose of carbachol, 3 μg/kg; 0 min: time for i.c.v. injection. *, P < 0.01 compared with the baseline level. OT: oxytocin.
Mentions: There was no significant difference in plasma AVP and OT levels between the control and the experimental ewes to i.c.v. injection (AVP: F8,1 = 0.37, OT: F8,1 = 0.23, both P > 0.05). However, the fetal AVP and OT concentrations were significantly increased after i.c.v. carbachol administration (AVP: F8,1 = 73.60, OT: F8,1 = 58.61, P < 0.01). In the control group, i.c.v. injection of the vehicle did not change the maternal and fetal plasma AVP or OT levels. The i.c.v. carbachol significantly increased fetal plasma AVP and OT levels (AVP: F28,6 = 43.23; OT: F28,6 = 35.40, respectively, both P < 0.01, the baseline period vs the period after i.c.v. injection) (Figure 1 and 2). Fetal plasma AVP and OT increased significantly within 15 minutes after i.c.v. carbachol, and the peak levels of plasma AVP and OT were observed at 30 minutes (AVP: from base line level 3.5 ± 1.2 to 53.4 ± 9.5 pg/ml; OT: from base line level 35.6 ± 6.0 to 228.3 ± 23.2 pg/ml) after injection of carbachol. There was no change in maternal plasma AVP and OT after i.c.v. injection of carbachol into the fetus.

Bottom Line: I.c.v. carbachol significantly increased fetal plasma AVP and OT concentrations.The results indicate that the central cholinergic mechanism is established and functional in the regulation of the hypothalamic neuropeptides during the final trimester of pregnancy.This provides evidence for a functional link between the development of central cholinergic mechanisms and hypothalamic neuropeptide systems in the fetus.

View Article: PubMed Central - HTML - PubMed

Affiliation: Perinatal Biology Center, Soochow University School of Medicine, Suzhou 215007, PR China. lshi@llu.edu

ABSTRACT

Background: The hypothalamic-neurohypophysial system plays a fundamental role in the maintenance of body fluid homeostasis by secreting arginine vasopressin (AVP) and oxytocin (OT) in response to a variety of signals, including osmotic and nonosmotic stimuli. It is well established that central cholinergic mechanisms are critical in the regulation of cardiovascular responses and maintenance of body fluid homeostasis in adults. Our recent study demonstrated that intracerebroventricular (i.c.v.) injection of carbachol elicited an increase of blood pressure in the near-term ovine fetuses. However, in utero development of brain cholinergic mechanisms in the regulation of the hypothalamic neuropeptides is largely unknown. This study investigated AVP and OT neural activation in the fetal hypothalamus induced by central carbachol.

Results: Chronically prepared near-term ovine fetuses (0.9 gestation) received an i.c.v. carbachol (3 microg/kg). Fetal blood samples were collected for AVP and OT assay, and brains were used for c-fos mapping studies. I.c.v. carbachol significantly increased fetal plasma AVP and OT concentrations. Intense FOS immunoreactivity (FOS-ir) was observed in the fetal supraoptic nuclei (SON) and paraventricular nuclei (PVN) in the hypothalamus. Double labeling demonstrated that a number of AVP- and OT-containing neurons in the fetal SON and PVN were expressing c-fos in response to central carbachol.

Conclusion: The results indicate that the central cholinergic mechanism is established and functional in the regulation of the hypothalamic neuropeptides during the final trimester of pregnancy. This provides evidence for a functional link between the development of central cholinergic mechanisms and hypothalamic neuropeptide systems in the fetus.

Show MeSH