The spectral sensitivity of cat retinal ganglion neurons (RGNs) was determined by means of extracellular recordings under scotopic and photopic conditions, in both receptive field center and surround. Test stimuli were presented either as square-wave single flashes or as flicker stimuli. Chromatic adaptation was achieved by a large steady monochromatic background field. In the dark-adapted stat...

A quantitative stereological analysis was undertaken in nucleoli of rat superior cervical ganglion neurons. In this model, two types of fibrillar centres were observed: (1) small-type fibrillar centres were observed during the light span; and (2) a single large-type fibrillar centre occurred during the dark span near the smaller ones. The present data showed that the drastic increase in the mea...

Dopamine is an important neurotransmitter regulating light-dark adaptation in the retina. The effect of dopamine is widespread and dependent on the localization of its receptors. We performed single cell RT-PCR on A-type horizontal cells visually selected from dissociated rabbit retinal neurons. Dopamine D1-receptor mRNA was positively identified. Subsequent sequencing of the fragment showed 82...

introduction: in iran, thousands of young individuals become victims of head injury annually. head injury can damage neuronal cells which may in turn complicate the recovery of the patients. also, the increase of iron in cerebrospinal fluid (csf) following head injury may contribute to the hypoxic-ischemia brain damage by catalyzing the formation of free radicals (harber-weiss rection). the obj...

objective(s): there are few reports have demonstrated the effect of a change-in-light experience on the structure and function of hippocampus. a change-in-light experience also affects the circadian pattern of melatonin secretion. this study aimed to investigate developmental effect of exogenous melatonin on synaptic plasticity of hippocampus of light deprived rats. materials and methods: the e...

PURPOSE To measure the dependence of the size of the pupils of mice on steady retinal illumination. METHODS Anesthetized C57BL/6 mice aged 7 to 8 weeks were placed in a ganzfeld chamber in darkness, and in monochromatic (510 nm) and white light whose intensity was varied more than 6 log units. The pupils of the mice were photographed with an infrared video camera and recorded on videotape and...

Ag-AS staining of nucleolar organizer regions was carried out on interphasic superior cervical ganglia neurons of rats sacrificed during light and dark periods. While the Ag-AS technique has mostly been used monolayer cell lines or cell suspensions, the present study showed that in electron microscopy this technique is also applicable to small pieces of tissues. The finest pictures are obtained...