Purinergic system exerts a significant influence on the modulation of pain pathways at the spinal... more Purinergic system exerts a significant influence on the modulation of pain pathways at the spinal site. Adenosine has antinociceptive properties in experimental and clinical situations, while ATP exerts pronociceptive actions in different pain models. In this study we investigated the hydrolysis of ATP to adenosine in synaptosomes from spinal cord in parallel with the nociceptive response of rats at different ages after hypothyroidism induction. Hypothyroidism elicited a significant increase in AMP hydrolysis to adenosine in synaptosomes from spinal cord of rats subjected to neonatal hypothyroidism and in 420-day-old rats submitted to thyroidectomy. Accordingly, these rats presented an analgesic response as a consequence of hypothyroidism. In contrast, the ATP hydrolysis was decreased in the spinal cord of 60-day-old hypothyroid rats in parallel with a significant increase in nociceptive response. These results indicate the involvement of adenine nucleotides in the control of the hypothyroidism-induced nociceptive response during development.
International Journal of Developmental Neuroscience, 2005
The influence of the thyroid hormones on the normal function of the mammalian central nervous sys... more The influence of the thyroid hormones on the normal function of the mammalian central nervous system depends on the brain region and on the developmental stage. Adenine nucleotides and their products also affect the brain function; ATP is an excitatory neurotransmitter, and adenosine has inhibitory effects on neurotransmission. Thus, this study aimed to evaluate the effects of hypothyroidism on the hydrolysis of ATP to adenosine in hippocampal and cortical synaptosomes and blood serum of rats during different phases of development. Rats aged 60 and 420 days old were divided into three groups: control, sham-operated and hypothyroid. Hypothyroidism was induced in these rats by thyroidectomy and methimazole (0.05%) added to their drinking water for 14 days. Neonatal hypothyroidism was induced by adding 0.02% methimazole in the drinking water from day 9 of gestation, and continually until 14 days old. Hypothyroidism increased the AMP hydrolysis in both hippocampus and cerebral cortex synaptosomes of rats in all aged tested. In blood serum, thyroid hormones deficiency increased the AMP hydrolysis in 14-day-old rats and the hydrolysis of ATP, ADP and AMP in 60-day-old rats; however, no alteration was observed in 420day-old rats. Thus, our results suggest the involvement of the 5 0 -nucleotidase in synaptic function control in hypothyroidism throughout brain development.
Increasing competition demands more competitiveness from companies and constant and accurate info... more Increasing competition demands more competitiveness from companies and constant and accurate information about competitors and the market place. This requires the development of performance evaluation methods. Although airport cargo revenues are larger than airport passenger's, no survey has provided a detailed study on competitive performance factors of air cargo players in Brazil. This paper has surveyed major airlines operating in Brazil and major air cargo dispatchers (domestic and international). The results of this work are directly useful to INFRAERO, to the airlines and to the Brazilian Civil Aviation Agency (ANAC), in order to suggest improvements in the efficiency of the air sector.
Purinergic system exerts a significant influence on the modulation of pain pathways at the spinal... more Purinergic system exerts a significant influence on the modulation of pain pathways at the spinal site. Adenosine has antinociceptive properties in experimental and clinical situations, while ATP exerts pronociceptive actions in different pain models. In this study we investigated the hydrolysis of ATP to adenosine in synaptosomes from spinal cord in parallel with the nociceptive response of rats at different ages after hypothyroidism induction. Hypothyroidism elicited a significant increase in AMP hydrolysis to adenosine in synaptosomes from spinal cord of rats subjected to neonatal hypothyroidism and in 420-day-old rats submitted to thyroidectomy. Accordingly, these rats presented an analgesic response as a consequence of hypothyroidism. In contrast, the ATP hydrolysis was decreased in the spinal cord of 60-day-old hypothyroid rats in parallel with a significant increase in nociceptive response. These results indicate the involvement of adenine nucleotides in the control of the hypothyroidism-induced nociceptive response during development.
International Journal of Developmental Neuroscience, 2005
The influence of the thyroid hormones on the normal function of the mammalian central nervous sys... more The influence of the thyroid hormones on the normal function of the mammalian central nervous system depends on the brain region and on the developmental stage. Adenine nucleotides and their products also affect the brain function; ATP is an excitatory neurotransmitter, and adenosine has inhibitory effects on neurotransmission. Thus, this study aimed to evaluate the effects of hypothyroidism on the hydrolysis of ATP to adenosine in hippocampal and cortical synaptosomes and blood serum of rats during different phases of development. Rats aged 60 and 420 days old were divided into three groups: control, sham-operated and hypothyroid. Hypothyroidism was induced in these rats by thyroidectomy and methimazole (0.05%) added to their drinking water for 14 days. Neonatal hypothyroidism was induced by adding 0.02% methimazole in the drinking water from day 9 of gestation, and continually until 14 days old. Hypothyroidism increased the AMP hydrolysis in both hippocampus and cerebral cortex synaptosomes of rats in all aged tested. In blood serum, thyroid hormones deficiency increased the AMP hydrolysis in 14-day-old rats and the hydrolysis of ATP, ADP and AMP in 60-day-old rats; however, no alteration was observed in 420day-old rats. Thus, our results suggest the involvement of the 5 0 -nucleotidase in synaptic function control in hypothyroidism throughout brain development.
Increasing competition demands more competitiveness from companies and constant and accurate info... more Increasing competition demands more competitiveness from companies and constant and accurate information about competitors and the market place. This requires the development of performance evaluation methods. Although airport cargo revenues are larger than airport passenger's, no survey has provided a detailed study on competitive performance factors of air cargo players in Brazil. This paper has surveyed major airlines operating in Brazil and major air cargo dispatchers (domestic and international). The results of this work are directly useful to INFRAERO, to the airlines and to the Brazilian Civil Aviation Agency (ANAC), in order to suggest improvements in the efficiency of the air sector.
Uploads
Papers by Felipe Sarkis