Glial fibrillary acidic protein immunoreactivity in the rat suprachiasmatic nucleus: circadian changes and their seasonal dependence
| Autor: | Ferenc Hajós, Balázs Gerics, Ferenc Szalay |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Male
medicine.medical_specialty Histology Photic Stimulation Biological clock Muscle hypertrophy Biological Clocks Internal medicine Glial Fibrillary Acidic Protein medicine Animals Circadian rhythm Rats Wistar Molecular Biology Ecology Evolution Behavior and Systematics Glial fibrillary acidic protein biology Suprachiasmatic nucleus Hypertrophy Original Articles Cell Biology Circadian Rhythm Rats Endocrinology nervous system Hypothalamus Astrocytes biology.protein Immunohistochemistry Suprachiasmatic Nucleus Seasons Anatomy Developmental Biology |
| Zdroj: | Journal of Anatomy. 209:231-237 |
| ISSN: | 1469-7580 0021-8782 |
| DOI: | 10.1111/j.1469-7580.2006.00593.x |
| Popis: | The pacemaker of the biological clock, the suprachiasmatic nucleus (SCN) of the hypothalamus, was studied in intact male rats to determine its immunoreactivity to glial fibrillary acidic protein (GFAP), a specific marker of astrocytes. Animals were kept under 12-h light-dark cycles in synchrony with day-night periods. Immunohistochemical reactions were carried out at midday and late at night in both winter (January) and summer (July). In winter, GFAP immunoreactivity was found to be low during the day and high at night. The findings were reversed in summer, when GFAP immunoreactivity was high during the day and low at night. Increased GFAP immunoreactivity appeared in the form of an abundance of thick immunopositive fibres rather than of cell bodies. This was interpreted as a hypertrophy of pre-existing astrocytes due to alternating photic stimulation conveyed by retinofugal fibres to the SCN. The observed seasonal reversal in the direction of GFAP oscillations raises the possibility that a circannual timer exists outside the SCN. |
| Databáze: | OpenAIRE |
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