Dual action of serotonin on local excitatory and inhibitory neural circuits regulating the corticotropin-releasing factor neurons in the paraventricular nucleus of the hypothalamus.

Serotonergic neurons originating from the raphe nuclei have been proposed to regulate corticotropin-releasing factor (CRF) neurons in the paraventricular nucleus of the hypothalamus (PVH). Since glutamate- and γ-aminobutyric acid (GABA)-containing neurons, constituting the hypothalamic local circuits, innervate PVH CRF neurons, we examined whether they mediate the actions of serotonin (5-hydroxytryptamine [5-HT]) on CRF neurons. Spontaneous excitatory postsynaptic currents (sEPSCs) or spontaneous inhibitory postsynaptic currents (sIPSCs) were recorded in PVH CRF neurons, under whole cell patch-clamp, using the CRF-modified yellow fluorescent protein (Venus) ΔNeo mouse.

Cholinergic modulation of CRH and non-CRH neurons in Barrington's nucleus of the mouse.

Corticotropin-releasing hormone (CRH) is expressed in Barrington's nucleus (BarN), which plays an essential role in the regulation of micturition. To control the neural activities of BarN, glutamatergic and GABAergic inputs from multiple sources have been demonstrated; however, it is not clear how modulatory neurotransmitters affect the activity of BarN neurons. We have employed knock-in mice, CRH-expressing neurons of which are labeled with a modified yellow fluorescent protein (Venus).

Distribution of corticotropin-releasing factor neurons in the mouse brain: a study using corticotropin-releasing factor-modified yellow fluorescent protein knock-in mouse.

We examined the morphological features of corticotropin-releasing factor (CRF) neurons in a mouse line in which modified yellow fluorescent protein (Venus) was expressed under the CRF promoter. We previously generated the CRF-Venus knock-in mouse, in which Venus is inserted into the CRF gene locus by homologous recombination. In the present study, the neomycin phosphotransferase gene (Neo), driven by the pgk-1 promoter, was deleted from the CRF-Venus mouse genome, and a CRF-Venus∆Neo mouse was generated.

Visualization of corticotropin-releasing factor neurons by fluorescent proteins in the mouse brain and characterization of labeled neurons in the paraventricular nucleus of the hypothalamus.

Corticotropin-releasing factor (CRF) is the key regulator of the hypothalamic-pituitary-adrenal axis. CRF neurons cannot be distinguished morphologically from other neuroendocrine neurons in the paraventricular nucleus of the hypothalamus (PVH) without immunostaining. Thus, we generated a knock-in mouse that expresses modified yellow fluorescent protein (Venus) in CRF neurons (CRF-Venus), and yet its expression is driven by the CRF promoter and responds to changes in the interior milieu.