Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A longitudinal study of developmental changes in the brainstem auditory evoked response (BAER) was made on 19 ferrets between postnatal days 25 (P25) and 50. Responses to free-field click stimuli were recorded from anaesthetized animals, and compared with data obtained from 8 adult ferrets. A reproducible BAER was first recordable on P27, although the response onset was generally later in smaller animals. BAER onset preceded eye opening, which started on P32. Adult-like thresholds were observed in all animals by P40, but the age at which they were attained was also dependent on size. The BAER in the adult ferret consists of 4 main vertex-positive peaks occurring in the first 5 ms following transient acoustic stimulation. In the youngest animals the presence of an additional peak (between II and III) and the slurring of peaks III and IV were consistent features. The individual peaks undergo an asymmetrical pattern of development, with mean peak I latency attaining an adult value at P40, while mean peak IV latency is still 115% of the mean adult value at that age. BAERs could routinely be recorded using high stimulus presentation rates (greater than 40/s), though an increase in absolute and interpeak latencies occurred, the extent of which decreased with age. The pattern of BAER development in the ferret is compared with that in other species, and the concept of the 'silent period' (period between conception and onset of hearing) as a standard unit of auditory development is introduced.
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PMID:Auditory brainstem of the ferret: maturation of the brainstem auditory evoked response. 233 96

It is widely believed that inhibitory synapses are not present or present in only small numbers in the rodent cerebral cortex during the early postnatal period when the cortex is being innervated by thalamocortical fibers. Quantitative electron microscopy was carried out on the posteromedial barrel subfield of mouse somatosensory cortex from postnatal day 4 (P4) when thalamocortical innervation of the barrels is becoming established, through to sexual maturity (>P32), and in adulthood. Both asymmetrical (putatively excitatory) and symmetrical (putatively inhibitory) synapses were present in all layers from P4. The symmetrical synapses were immunoreactive for GABA at all ages. There was a progressive increase in both asymmetrical and symmetrical synapses up to P32, density in all layers increasing 16-fold, with the production of asymmetrical synapses leading and greatly outstripping that of symmetrical. From P32 to P120, the oldest age studied, synaptic numbers declined by 18% to 13 times the P4 level, but this affected predominantly layers II/III, IV and V, and mainly involved asymmetrical synapses. The relative percentage of asymmetrical to symmetrical synapses from P4 to P8 was 57%/43% but at P32 it was 89.5%/10.5% and in adulthood 85.4%/14.6%. These data indicate that inhibitory synaptogenesis in the rodent cortex begins earlier than previously thought, a basis for inhibition being present from the earliest period. Pruning of all synapses occurs well after thalamocortical innervation is established and inhibitory synapses are less affected by the pruning process.
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PMID:Inhibitory synaptogenesis in mouse somatosensory cortex. 937 18