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Biomedical subjects

S Trojan

Publications and source records attributed to S Trojan.

At least 163 records · Page 9Linked to original sources
PubMed1980

The ontogenesis of cortical self-sustained after-discharges in rats.

An ontogenetic development of cortical self-sustained after-discharges (SSADs) was studied in acute experiments on 98 male albino rats aged from 9 days to adulthood. Rhythmic electrical stimulation of one cortical sensorimotor area regularly elicited SSADs formed by spike-and-wave complexes starting from the postnatal day 15. Frequency of these complexes increased from 2.0 to 2.5 cycles/s in 15- and 18-day-old rats to 3.0 to 4.0 cycles/s in older animals. In younger animals SSADs were better expressed in the stimulated sensorimotor than in the visual area of both hemispheres, whereas in older rats the SSADs were fully generalized. The SSADs became longer with increasing age. A highly significant prolongation of the SSADs was seen in all age groups with repeated stimulations; this finding is discussed as a possible form of kindling.

Age Factors↗
PubMed1980

Changes in the length and width of the postsynaptic density, the width of the intersynaptic density and the synaptic cleft in the cerebral cortex synapses of rats exposed to prolonged aerogenic hypoxia during early ontogenesis. An electron microscopic morphometric study.

Infant rats, together with the female, were exposed daily from birth to the age of 17 days (except for the 6th, 7th, 13th and 14th day) to a simulated attitude of 7,000 m. On the 18th day, 20 hours after the last exposure to hypoxia, the animals were perfused. In each of 118 synapses from the two control animals and 162 synapses from the two experimental animals (type I synapses, second cortical layer of the somatosensory cortex, impregnated with phosphotungstic acid), we measured A) the maximal thickness of the postsynaptic density and B) the minimal thickness of the postsynaptic density, C) estimated the thickness of the postsynaptic density and measured D) the distance between the pre- and the postsynaptic density, E) the thickness of the intersynaptic density and F) the length of the postsynaptic dense projection. In the experimental animals we found value A) to be 25% lower, value B) 28% lower, value C) 30% lower, value D) 5% lower, value E) 2.5% lower and value F) 17% higher than in the controls. The differences are statistically significant (evaluated by a t-test). It was found that, under our experimental hypobaric conditions, the maturation of synapses is retarded or modified.

Animals↗
PubMed1979

Ontogenetic development of pentobarbital-induced EEG pattern and sleeping time in rats.

The latency of onset and the duration of sleep induced by pentobarbital was studied in rats from 9 to 35 days of age, as well as in adult rats. Sleep latency was prolonged and sleep duration shortened with increasing age and maturation. Electrocorticographic changes after pentobarbital administration were studied in rats of 5-45 days of age and in adult rats. In rats 9 days of age or less the electrocorticogram manifested only depression of activity, whereas from the 12th day onward all characteristic barbiturate-induced phenomena were registered: spindles, slow waves, and isolated spikes with suppression of background activity. Spindles were the most conspicuous of the pentobarbital-induced phenomena and were the 1st to appear as a function of age, occurring only in the frontal areas of 12 days of age but in both frontal and occipital areas at 15 days of age. Frequency of the elements comprising spindles increased with from 2.5-3.5 c/sec in 12-day-old rats to 5-10 c/sec in adult animals. Barbiturate spindles could be used as a model for rhythmic thalamocortical phenomena even at early stages of development.

Animals↗