Vias angiotensinérgicas e colinérgicas centrais no controle da ingestão de água e sódio em animais submetidos a sessões de esteira
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Data
2020-06-17
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Universidade Federal de Goiás
Resumo
Physical exercise can promote adaptations and decrease neuronal sensitivity in stressful situations,
due to neuroplasticity, with cases of intracellular and extracellular dehydration depending on the
intensity of the activity. Intracellular dehydration is the loss of water by the cell due to increased
osmotic pressure in the extracellular compartment and appears to be involved in central cholinergic
pathways. Extracellular dehydration, however, is the joint loss of water and sodium, decreasing
extracellular compartment volume. Angiotensin II (ANG II), acting centrally, activates autonomic
and behavioral control mechanisms due to the activation of AT1 receptors after dehydration. The
aim of the present study was to evaluate the effects of ANG II and carbacol (cholinergic agonist)
central injection on the behavior of water and sodium intake in rats submitted to treadmill sessions.
Wistar rats (250-280g) were separated into two groups: Sedentary and Trained. 8 weeks of
treadmill training were carried out. At the end, under anesthesia, a guide cannula was implanted in
the lateral ventricle (VL). After 5 recovery days, central microinjection (1 µL) of saline and ANG
II (50 ng) was performed on animals with free movement, water and 1.8% NaCL intakes were
measured at times 15, 30, 45, 60, 90 and 120 minutes. Urine was collected after each experiment.
After 2 days, the animals were subjected again to the water and sodium intake experiment, with a
central micro injection of carbacol (4 nmol in 1 µL). Subsequently, the animals were euthanized,
and the brains removed for histological analysis. The results showed that ANG II was able to
promote water intake in both groups, Trained rats (8.2 ± 11.2 vs. Control: 0.1 ± 0.1 mL / 120 min,
p <0.05) and Sedentary (6.0 ± 7.4 mL vs. Control: 0.1 ± 0.3 mL / 120 min, p <0.05); in relation to
sodium: Sedentary (6.3 ± 7.3 vs Control: 0.5 ± 1.3 mL mL / 120 min, p <0.05) and Trained (6.9 ±
7.2 vs. Control 1 , 3 ± 1.5 mL / 120 min, p <0.05) without differences between Trained and
Sedentary groups. Carbacol, in contrast, induced water intake in Sedentary (8.7 ± 6.1 vs. Control:
0.6 ± 0.7 mL / 120 min, p <0.05) and Trained (9.5 ± 8.3 vs. Control: 1.4 ± 2.4 mL / 120 min, p
<0.05), and in relation to sodium intake, it was observed that in the Trained (3.7 ± 3.8 vs. Control:
0.8 ± 1.4 mL / 120 min, p <0.05) and Sedentary (0.3 ± 0.3 vs. Control: 0.5 ± 0.8 mL / 120 min, p>
0.05), with significant difference between groups. Thus, the results showed that the training did not
alter the water behavior induced by centrally ANG II or carbacol, and also sodium intake caused
by ANG II, however induced sodium intake by carbacol suggesting that the central
angiotensinergic and cholinergic pathways that control dipsogenic response are not affected by
physical training, but cholinergic pathway could be involved in sodium apetite.
Descrição
Palavras-chave
Angiotensina II, Apetite ao sódio, Carbacol, Exercício físico, Ingestão de água, Neuroplasticidade, Angiotensin II, Sodium apetite, Carbachol, Physical exercise, Water intake, Neural plasticity
Citação
SOUZA, Ariel Alves de. Vias angiotensinérgicas e colinérgicas
centrais no controle da ingestão de água e sódio em animais
submetidos a sessões de esteira. 2020. 36 f. Trabalho de Conclusão de
Curso (Graduação) – Faculdade de Farmácia, Universidade Federal
de Goiás, Goiânia, 2020.