Spatial segregation within the sacral parasympathetic nucleus of neurons innervating the bladder or the penis of the rat as revealed by three-dimensional reconstruction.

The purpose of the present investigations was (1) to examine the spatial organization of preganglionic neurons of the sacral parasympathetic nucleus in the lumbosacral spinal cord of male adult rats and (2) to search, in this nucleus, for a possible segregation of sub-populations of neurons innervating the penis or the bladder, respectively. To estimate their spatial organization, neurons of the sacral parasympathetic nucleus were retrogradely labeled by wheat germ agglutinin coupled to horseradish peroxidase applied to the central end of the sectioned pelvic nerve. The sub-populations of lumbosacral neurons innervating the corpus cavernosum of the penis or the dome of the bladder were identified using transsynaptic retrograde labeling by pseudorabies virus injected into these organs in different rats.

Neurons that express the AMPA receptor GluR2/3 subunits in suprachiasmatic nuclei of Syrian hamsters colocalize either vasoactive intestinal peptide, peptide histidine isoleucine or gastrin-releasing peptide.

In mammals, many circadian rhythms are driven by a clock located inside the suprachiasmatic nucleus of the hypothalamus. They are synchronized to environmental light-dark cycles by information coming directly from the retina via glutamatergic afferents. In rodents, retinal fibres make direct synaptic contacts with neurons synthesizing vasoactive intestinal peptide and gastrin-releasing peptide.

Neurons containing gastrin-releasing peptide and vasoactive intestinal polypeptide are involved in the reception of the photic signal in the suprachiasmatic nucleus of the Syrian hamster: an immunocytochemical ultrastructural study.

In mammals, the suprachiasmatic nuclei are involved in the generation of biological rhythms and are synchronized by light input coming from the retina. The targets of retinal afferents and the involvement of neurons containing gastrin-releasing and vasoactive intestinal peptides in photic reception were investigated in the suprachiasmatic nuclei of the Syrian hamster by using light- and electron-microscopic immunocytochemistry. Cholera toxin was used to trace retinal fibers and Fos immunoreactivity to visualize cellular response to light stimulation.

Estrogen receptor and progesterone receptor-immunoreactive cells are not co-localized with gonadotropin-releasing hormone in the brain of the female mink (Mustela vison).

The distribution of gonadal steroid (estrogen, progesterone) receptors in the brain of the adult female mink was mapped by immunocytochemistry. Using a monoclonal rat antibody raised against human estrogen receptor (ER), the most dense collections of ER-immunoreactive (IR) cells were found in the preoptic/anterior hypothalamic area, the mediobasal hypothalamus (arcuate and ventromedial nuclei), and the limbic nuclei (amygdala, bed nucleus of the stria terminalis, lateral septum). Immunoreactivity was mainly observed in the cell nucleus and a marked heterogeneity of staining appeared from one region to another.

Ontogenesis of the retinohypothalamic tract, vasoactive intestinal polypeptide- and peptide histidine isoleucine-containing neurons and melatonin binding in the hypothalamus of the mink.

The development of the retinohypothalamic tract (RHT) labeled with cholera toxin and of the vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine (PHI) systems was studied in the hypothalamus of neonatal mink by using immunohistochemistry. Retinal fibers were observed in the suprachiasmatic nucleus (SCN) from birth and were adult-like by day 14. VIP and PHI immunoreactivity was also present from birth.