مرکز منطقه ای اطلاع رساني علوم و فناوري - Developmental investigation of neurochemical features in tegmental pedunculopontine nucleus

Abstract :

Objective: Pedunculopontine nucleus (PPN) is a brainstem nucleus with an obscure border and located in the caudal tegmentum. In recent years, the numbers of studies related to PPN have been increasing due to its role in sleep/waking, in behavior, learning, and attention as well as its role in generation and control of locomotion. Besides cholinergic neurons, there are GABAergic, glutamatergic, dopaminergic and noradrenergic neurons in the PPN. Recently, the PPN has been a target for treatment of axial semptoms in Parkinson disease (PD). Calbindin, a member of the calcium binding protein family, which is an important molecule during protein synthesis has been related to neurodegenerative diseases. In our study, we investigated the developmental differences of calbindin expression which is related to GABAergic and glutamatergic neurons. Materials and Methods: The borders of the PPN were determined on the basis of the distribution of cholinergic neurons. Calbindin is expressed by GABAergic and glutamatergic neurons. Wistar rats aged 7, 14 and 21 days were perfused through the heart with a 4% paraformaldehyde solution. Brains were removed and 40 μm plane of sections were cut via microtome. Free-floating slices were stained with anti choline asetyltransferase and calbindin. In our study, we used 4 rats for each group, totally 12 rats were utilized. The number, location and diameters of calbindin positive neurons in PPN were evaluated in 7, 14 and 21 day-old rats. Results: The mean numbers of neurons were 30 ±3 at 7 days, 11 ±1 at 14 days and 150±50 at 21 days rats. There were statistically significant differences between 7 and 14 days and 14 and 21 day-old rats (p=0.0075 ve p=0.0343 respectively). The diameters of the neurons were 13 ±1.4 μm at 7 days, 11±1.6 μm at 14 days; 13.5±1.1μm at 21days. Conclusion: This study indicates that critical developmental changes in PPN occur between these intervals. These findings support and contribute to the findings of previous studies.