| First Author | Brown TM | Year | 2005 |
| Journal | J Neurosci | Volume | 25 |
| Issue | 48 | Pages | 11155-64 |
| PubMed ID | 16319315 | Mgi Jnum | J:123043 |
| Mgi Id | MGI:3716273 | Doi | 10.1523/JNEUROSCI.3821-05.2005 |
| Citation | Brown TM, et al. (2005) Gastrin-releasing peptide promotes suprachiasmatic nuclei cellular rhythmicity in the absence of vasoactive intestinal polypeptide-VPAC2 receptor signaling. J Neurosci 25(48):11155-64 |
| abstractText | Vasoactive intestinal polypeptide (VIP) and gastrin-releasing peptide (GRP) acting via the VPAC2 receptor and BB2 receptors, respectively, are key signaling pathways in the suprachiasmatic nuclei (SCN) circadian clock. Transgenic mice lacking the VPAC2 receptor (Vipr2(-/-)) display a continuum of disrupted behavioral rhythms with only a minority capable of sustaining predictable cycles of rest and activity. However, electrical or molecular oscillations have not yet been detected in SCN cells from adult Vipr2(-/-) mice. Using a novel electrophysiological recording technique, we found that in brain slices from wild-type and behaviorally rhythmic Vipr2(-/-) mice, the majority of SCN neurons we detected displayed circadian firing patterns with estimated periods similar to the animals' behavior. In contrast, in slices from behaviorally arrhythmic Vipr2(-/-) mice, only a small minority of the observed SCN cells oscillated. Remarkably, exogenous GRP promoted SCN cellular rhythms in Vipr2(-/-) mouse slices, whereas blockade of BB2 receptors suppressed neuronal oscillations. In wild-type mice, perturbation of GRP-BB2 signaling had few effects on SCN cellular rhythms, except when VPAC2 receptors were blocked pharmacologically. These findings establish that residual electrical oscillations persist in the SCN of Vipr2(-/-) mice and reveal a potential new role for GRP-BB2 signaling within the circadian clock. |
