Circadian rhythms of dopamine and cholecystokinin in nucleus accumbens and striatum of rats--influence on dopaminergic stimulation
| Autor: | R. Schade, G. Golor, J. Bellach, C. Pfister, K. Vick, T. Ott, R. Sohr, Björn Lemmer |
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| Rok vydání: | 1995 |
| Předmět: |
Male
medicine.medical_specialty Time Factors Light Physiology Dopamine Neuropeptide Striatum Nucleus accumbens Nucleus Accumbens 4-Butyrolactone Physiology (medical) Internal medicine Basal ganglia medicine Animals Circadian rhythm Rats Wistar GABA Modulators Thyrotropin-Releasing Hormone Cholecystokinin Chemistry digestive oral and skin physiology Dopaminergic Darkness Corpus Striatum Circadian Rhythm Rats Endocrinology Organ Specificity hormones hormone substitutes and hormone antagonists medicine.drug |
| Zdroj: | Chronobiology international. 12(2) |
| ISSN: | 0742-0528 |
| Popis: | The concentrations of cholecystokinin (CCK) and dopamine (DA) were determined in the nucleus accumbens (anterior, posterior) and striatum of rats every 2 h during a period of 24 h. For both substances, a circadian rhythm was found, which was best fitted by a dominant 24-h period superimposed by the second (12 h) and fourth (6 h) harmonics. The rhythms in CCK and DA were negatively correlated because of a difference in phase position by approximately 3 h. A dominant DA peak was found in the light phase coinciding with a trough in CCK and vice versa in the dark phase. Based on these data, CCK and DA were determined in rats treated with gamma-butyrolactone (GBL; inhibitor of DA release) or thyrotropin-releasing hormone (TRH; stimulator of DA release) at 0900 h or 1300 h to study a putative time-dependency in drug effects. After GBL treatment, CCK as well as DA increased by up to 200% whereas TRH administration led to a rather complex alteration, inasmuch as CCK was increased or decreased, depending on circadian time, whereas the rhythmic pattern in DA remained relatively unaffected. Comparing the drug effects obtained at 0900 h with the response seen at 1300 h revealed significant quantitative as well as qualitative differences. The results demonstrate that the neurotransmission system investigated changed its level of activity depending on time of day. No changes were obtained that convincingly may be ascribed to colocalization of DA and CCK. It is concluded that the chronobiological data indicate a close interaction of CCK and DA in various areas of the rat brain, independent of colocalization. |
| Databáze: | OpenAIRE |
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