Release of Cholecystokinin-Like Immunoreactivity in the Frontal Cortex of Conscious Rats as Assessed by Transcerebral Microdialysis: Effects of Different Depolarizing Stimuli
| Autor: | Paolo Paudice, F. Vallebuona, Maurizio Raiteri |
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| Rok vydání: | 2006 |
| Předmět: |
Male
medicine.medical_specialty Microdialysis Neuropeptide Tetrodotoxin digestive system Biochemistry Rats Sprague-Dawley Veratrine Cellular and Molecular Neuroscience chemistry.chemical_compound Internal medicine medicine Animals 4-Aminopyridine Cholecystokinin Chemistry digestive oral and skin physiology Radioimmunoassay Depolarization Frontal Lobe Rats Electrophysiology Endocrinology Anesthesia Potassium Calcium Dialysis hormones hormone substitutes and hormone antagonists medicine.drug |
| Zdroj: | Journal of Neurochemistry. 61:490-495 |
| ISSN: | 0022-3042 |
| DOI: | 10.1111/j.1471-4159.1993.tb02150.x |
| Popis: | The release of cholecystokinin-like immunoreactivity (CCK-LI) from the frontal cortex of freely moving rats has been studied using a transcerebral microdialysis technique coupled to a radioimmunoassay procedure. Basal levels of CCK-LI in the dialysate were above detection limits (2.4 +/- 0.7 pg/20 min; n = 8). High-K+ media evoked CCK-LI overflow in a concentration-dependent manner. The threshold concentration was 50 mM KCl. The peak overflow evoked by 100 mM K+ amounted to 42.7 +/- 2.8 pg/20 min (n = 6); it was totally Ca2+ dependent but insensitive to 1 microM tetrodotoxin. Infusion of 4-aminopyridine (1 mM; 20 min) evoked an overflow of CCK-LI (32 +/- 2.3 pg/20 min; n = 4), which was totally Ca2+ dependent and tetrodotoxin sensitive. Depolarization with 100 micrograms/ml of veratrine (20 min) provoked a CCK-LI overflow (62.2 +/- 10 pg/20 min; n = 6), which was also blocked by tetrodotoxin or by the absence of Ca2+ ions. The CCK-LI material collected under basal conditions or during veratrine infusion consisted essentially of CCK octapeptide sulfate. The veratrine-induced CCK-LI overflow did not change significantly when the infusion time was prolonged to 100 min. A second 20-min stimulus with 100 micrograms/ml of veratrine applied 200 min after a first 20-min stimulus evoked a barely significant CCK-LI overflow. These data suggest that one single 20-min stimulus with 100 micrograms/ml of veratrine may be sufficient to deplete the CCK-LI releasable stores and that > 200 min are required to replenish the depleted CCK-containing vesicles.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Databáze: | OpenAIRE |
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