Molecular background and physiological consequences of altered peripheral serotonin homeostasis in adult rats perinatally treated with tranylcypromine.

Serotonin (5-hydroxytryptamine, 5-HT) is a biologically active molecule present in mammals in the brain and peripheral tissues where it exerts many physiological functions. Developmental exposure to 5-HT-enhancing agents has been reported to induce long-lasting changes in the brain, but the long-term effects of perinatal 5-HT enhancement on 5-HT balance and function in the peripheral compartment have not been explored. Perinatal treatment of rats with monoamine oxidase (MAO) inhibitor tranylcypromine (TCP), leads to persistent imbalance in central (increased 5-HT degradation and decreased 5-HT concentrations in the brain) and peripheral (increased platelet and decreased plasma 5-HT concentrations) 5-HT homeostasis. In this study, we explored the molecular background of peripheral 5-HT imbalance, and its possible consequences on bone remodeling and hematopoiesis. Jejunum, liver and blood samples were collected from TCP- and saline-treated rats on post-natal day 70. Relative mRNA levels for tryptophan hydroxylase 1 (TPH1) and MAO A were analyzed using quantitative RT-PCR, femoral trabecular bone parameters were measured using microcomputed tomography, while peripheral blood cell number was determined by cell counter. TCP-treated rats displayed significant decrease in expression of Tph1, and significant increase in percentage of bone volume, trabecular number, connectivity density, and leukocyte number. In addition, significant negative correlation was observed between relative concentrations of TPH1 mRNA and trabecular bone parameters. Our results: a) show that perinatal exposure to tranylcypromine leads to long-lasting compensatory decrease in Tph1 expression in the peripheral compartment, accompanied with alterations in bone remodeling and hematopoiesis, b) suggest that peripheral and central 5HT compartment use different strategies to compensate for 5-HT imbalances of the same cause, and c) indicate dominant role of peripheral over central 5-HT in the regulation of bone maintenance, as well as possible negative in vivo influence of peripheral 5-HT on leukocyte development and/or sustainment.

Phylogenetically conditioned possibilities of the realization and of the development of complex movements at the age of 7 years.

Upon entering a school the seven-year olds (+/- 2 months) underwent a systematic, experimental, specially programmed, eighteen-month-long transformational procedure. The objective of the procedure was to develop the abilities and to observe the growth and the development of children, both girls and boys. The data were processed by means of discriminant analyses in each of the three control points. There was a total sample of 487 children. With regard to the phylogenetic characteristics of a human, it may be said that the basic abilities connected with phylogenetic development may be clearly recognized, precisely in such a way that children replicate this development throughout their earliest childhood. Most probably, the basic ability was the ability to maintain a postural balance, followed by the ability of movement control. Then came object manipulation by upper extremities, followed by the significance of resistance to inertial forces while moving, and ultimately the control of complex movements of the whole body.