In this study, we used an experimental model of congenital hypothyroidism to show that deficient thyroid hormones (TH) disrupt different neurochemical, morphological and functional aspects in the cerebral cortex of 15-day-old offspring. Our results showing decreased glutamine synthetase (GS) activity and Ca2+ overload in the cerebral cortex of hypothyroid pups suggest misregulated glutamate metabolism associated with developmentally induced TH deficiency. The 14C-MeAIB accumulation indicates upregulated System A activity and glutamine uptake by neurons. Energy metabolism in hypothyroid cortical slices was preserved, as demonstrated by unaltered glucose metabolism. We also found upregulated acetylcholinesterase activity, depleting acetylcholine from the synaptic cleft, pointing to disrupted cholinergic system. Increased reactive oxygen species (ROS) generation, lipid peroxidation, glutathione (GSH) depletion, which were associated with glutathione peroxidase, superoxide dismutase and gamma-glutamyltransferase downregulation suggest redox imbalance. Disrupted astrocyte cytoskeleton was evidenced by downregulated and hyperphosphorylated glial fibrillary acidic protein (GFAP). Morphological and structural characterization of the sensorimotor cerebral cortex (SCC) showed unaltered thickness of the SCC. However, decreased size of neurons on the layers II & III and IV in the right SCC and increased NeuN positive neurons in specific SCC layers, suggest that they are differently affected by the low TH levels during neurodevelopment. Hypothyroid pups presented increased number of foot-faults in the gridwalk test indicating affected motor functions. Taken together, our results show that congenital hypothyroidism disrupts glutamatergic and cholinergic neurotransmission, Ca2+ equilibrium, redox balance, cytoskeleton integrity, morphological and functional aspects in the cerebral cortex of young rats.
Hypothyroidism/chemically induced , Sensorimotor Cortex/enzymology , Acetylcholinesterase/metabolism , Animals , Animals, Newborn , Antigens, Nuclear/metabolism , Behavior, Animal , Biological Transport , Body Composition , Cells, Cultured , Cerebral Cortex/enzymology , Female , Glial Fibrillary Acidic Protein/metabolism , Glucose/metabolism , Glutamate-Ammonia Ligase/metabolism , Glutamic Acid/metabolism , Hypothyroidism/blood , Hypothyroidism/physiopathology , L-Lactate Dehydrogenase/metabolism , Molecular Docking Simulation , Motor Activity , Nerve Tissue Proteins/metabolism , Oxidation-Reduction , Phosphorylation , Propylthiouracil , Rats, Wistar , Receptors, Cytoplasmic and Nuclear/metabolism , Thyroid Gland/metabolism , Thyroid Hormones/blood
In this study we evaluated floristic composition patterns of communities of climbers within ten inventories carried out in semideciduous forest fragments of southeastern Brazil. One of the inventories is original, being carried out for the present study in Ribeirão Cachoeira forest, Campinas, São Paulo State, Southeastern Brazil. This inventory was then pooled together to other nine climbers' inventories made in other forests of Southeastern Brazil to form a data base, which was examined regarding species richness, similarity, species distribution and climbing methods. The total number of species obtained was 355, belonging to 145 genera and 43 families. The ten most diverse families Bignoniaceae (45 species), Fabaceae (42), Malpighiaceae (36), Asteraceae (31), Apocynaceae (29), Sapindaceae (28), Convolvulaceae (21), Cucurbitaceae (14), Passifloraceae (10), and Euphorbiaceae (8) contributed to 74.4 percent of the total number of species recorded. The commonest climbing method in the studied sites was main stem or branch twining, accounting for 178 species or 50.1 percent of the total, the second commonest was tendril climbing (121 species, 34.1 percent), and the least, scrambling (56 species, 15.8 percent). We found a high percentage of exclusive species i.e., those occurring in only one forest site, which accounted for 49.3 percent of the total recorded. The mean similarity among forest sites (30 percent) may be considered low. The climbing species contribution to the total wood plant richness recorded on the forests sites was very high in some of the sites (up to 52.5 percent). These results indicated the importance of climber communities to plant diversity for semideciduous forests in Southeastern Brazil, enhancing the regional diversity and the conservation value of these forest remnants.
No presente estudo avaliamos as variações na composição de espécies das comunidades de trepadeiras abordando dez inventários florísticos realizados em fragmentos de floresta estacional semidecidual do sudeste do Brasil. Um destes inventários é inédito e foi realizado especialmente para o presente estudo. Comparamos este levantamento a outros nove inventários florísticos de trepadeiras realizados em outras florestas do sudeste para investigar aspectos como riqueza, similaridade, distribuição de espécies e mecanismos de escalada. Ao todo foram encontradas 355 espécies, pertencentes a 145 gêneros e 43 famílias. As dez famílias mais ricas Bignoniaceae (45 espécies), Fabaceae (42), Malpighiaceae (36), Asteraceae (31), Apocynaceae (29), Sapindaceae (28), Convolvulaceae (21), Cucurbitaceae (14), Passifloraceae (10), e Euphorbiaceae (8) representaram 74,4 por cento do total de espécies encontrado. Considerando os mecanismos de escalada, observamos o predomínio de espécies volúveis (178 espécies ou 50,1 por cento), sobre espécies com gavinhas (121 espécies, 34,1 por cento), e apoiadoras (56 espécies, 15,8 por cento). A porcentagem de espécies exclusivas, i.e. aquelas que ocorreram em apenas uma das localidades estudadas, foi de 49,3 por cento do total amostrado e pode ser considerada alta. Além disso, a similaridade entre as florestas analisadas foi bastante baixa e a contribuição das espécies de trepadeiras para a diversidade de plantas lenhosas nestas áreas foi bastante elevada em algumas áreas, chegando a 52,5 por cento. Estes resultados indicaram a importância das comunidades de trepadeiras para a diversidade vegetal nas florestas semideciduais do sudeste do Brasil, aumentando a valor de conservação desses remanescentes florestais.
