Early X-irradiation of rats. 5. Influence of irradiation on the development of extracellular field potentials evoked by antidromic stimulation.
Rat pups were treated by low, fragmented and repeated doses of X-rays, from late prenatal days until the end of the third postnatal week. Extracellular field potentials, evoked by antidromic stimulation of the lateral olfactory tract were recorded in different layers of the olfactory bulb at 1, 2, 3 and 6 weeks of age, from control (non-irradiated) and experimental rats. Development of the field potentials was analysed in both groups of animals. In controls, the amplitude of responses was gradually increasing along with age while the latency of peaks decreased; inhibitory waves were tuned even after the third postnatal week. When compared to controls at similar ages, irradiated rats had smaller peak amplitude of responses and the shortening of the response latency was delayed. In addition, a new, late-appearing excitatory wave component was observed in the granule cell layer by the sixth week. The effect of irradiation on field potentials of the olfactory bulb is discussed in light of the marked reduction of the inhibition in the local neuronal assembly, which is also indicated by the depressed development of its structural and neurochemical correlates.
Mészáros
M
M
Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged.
Szente
M B
MB
Baranyi
A
A
Halász
N
N
D000818:Animals; D001921:Brain / Q000648:ultrastructure; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000528:radiation effects*; D005110:Extracellular Space / Q000528:radiation effects*; D005260:Female; D008297:Male; D009830:Olfactory Bulb / Q000033:anatomy & histology / Q000502:physiology / Q000528:radiation effects*; D011247:Pregnancy; D011833:Radiation Injuries, Experimental / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains