AGE CHANGES OF CELLULAR COMPOSITION OF RAT MAJOR PELVIC GANGLION IN NORM AND AFTER DESYMPATHIZATION

The neurons of major pelvic ganglion (MPG) were studied in 140 female Wistar rats of different ages (from newborns up to 180 days). For desympathization, experimental animals were daily intraperitoneally injected with 0.3 ml guanethidine (60-70 mg/kg) from Day 3 to Day 29. To detect the peculiarities of development, the cross-sectional area of neuronal cell bodies and the characteristics of the histograms of their cellular composition were evaluated. The periods of intensive growth in the size of neurons were detected: from Day 5 till Day 10, from Day 14 till Day 30 and from Day 60 till Day 90. These periods were followed by a relative stabilization of the parameter, indicating the stepwise nature of the process. Final stabilization of MPG neuronal populations occurred at Day 90. Desympathization caused the death of a part of a population of neurons, and disruption of normal age-related dynamics of their growth. Phase response to the injection of the neurotoxin was found in MPG. From Day 14 till Day 21, an average cross-sectional area of the cells was below normal, while from Day 21 till Day 60 it exceeded the control values. From Day 90 till Day 180, the cross-sectional area of neurons decreased, becaming lower than in control, indicating a secondary neurodystrophic process. The absence of class 5-7 large neurons after desympathization reflects not only the delay of their growth, but also the inability of surviving neurons to compensatory hypertrophic reactions as a result of disruption of trophic influences.

pelvic ganglia, neurons, guanethidine, desympathization, histograms