AMPA glutamatergic receptor-immunoreactive subunits are expressed in lumbosacral neurons of the spinal cord and neurons of the dorsal root and pelvic ganglia controlling pelvic functions in the rat.

Sacral preganglionic neurons innervate the pelvic organs via a relay in the major pelvic ganglion. Pudendal motoneurons innervate striated muscles and sphincters of the lower urinary, genital and digestive tracts. The activity of these spinal neurons is regulated by sensory afferents of visceral and somatic origins.

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.

Circadian rhythm of AMPA receptor GluR2/3 subunit-immunoreactivity in the suprachiasmatic nuclei of Syrian hamster and effect of a light-dark cycle.

In mammals, the suprachiasmatic nuclei (SCN) of the hypothalamus are the site of the circadian clock that generates and coordinates many endogenous physiological and behavioral rhythms. SCN are normally entrained to light/dark (LD) cycle by direct retinal afferents using glutamate as neurotransmitter. N-Methyl-d-aspartate (NMDA) and non-NMDA receptors are involved in photic entrainment of SCN.

Temporospatial characteristics of light-induced fos immunoreactivity in suprachiasmatic nuclei are not modified in Syrian hamsters treated neonatally with monosodium glutamate.

Neonatal treatment of rodents by intraperitoneal injections of monosodium glutamate (MSG) destroys many retinal ganglion cells whose neurons belong to the circadian system; howertheless, adults always synchronize their locomotor activity rhythm (LAR) to the light/dark cycle. Recent studies have shown that light-induced phase shifts of LAR are associated with the c-fos induction in suprachiasmatic nuclei (SCN) of nocturnal rodents. In this study, the circadian system was analyzed in treated and control hamsters maintained in constant darkness and exposed to light at circadian times (CTs) 13 and 18 during subjective night, 1 and 6 h after the onset of LAR.

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.