Catecholaminergic neurons in the comissural region of the nucleus of the solitary tract modulate hyperosmolality-induced responses
Carregando...
Data
2015
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
Catecholaminergic neurons in
the comissural region of the nucleus of the solitary tract modulate
hyperosmolality-induced responses. Am J Physiol Regul Integr Comp
Physiol 309: R1082–R1091, 2015. First published September 2, 2015;
doi:10.1152/ajpregu.00432.2014.—Noradrenergic A2 neurons of the
nucleus of the solitary tract (NTS) have been suggested to con tribute to body fluid homeostasis and cardiovascular regulation. In
the present study, we investigated the effects of lesions of A2
neurons of the commissural NTS (cNTS) on the c-Fos expression
in neurons of the hypothalamic paraventricular (PVN) and su praoptic (SON) nuclei, arterial pressure, water intake, and urinary
excretion in rats with plasma hyperosmolality produced by intra gastric 2 M NaCl (2 ml/rat). Male Holtzman rats (280 –320 g)
received an injection of anti-dopamine- -hydroxylase-saporin
(12.6 ng/60 nl; cNTS/A2-lesion, n 28) or immunoglobulin G
(IgG)-saporin (12.6 ng/60 nl; sham, n 24) into the cNTS. The
cNTS/A2 lesions increased the number of neurons expressing
c-Fos in the magnocellular PVN in rats treated with hypertonic
NaCl (90 13, vs. sham: 47 20; n 4), without changing the
number of neurons expressing c-Fos in the parvocellular PVN or in
the SON. Contrary to sham rats, intragastric 2 M NaCl also
increased arterial pressure in cNTS/A2-lesioned rats (16 3, vs.
sham: 2 2 mmHg 60 min after the intragastric load; n 9), an
effect blocked by the pretreatment with the vasopressin antagonist
Manning compound (0 3 mmHg; n 10). In addition, cNTS/A2
lesions enhanced hyperosmolality-induced water intake (10.5
1.4, vs. sham: 7.7 0.8 ml/60 min; n 8 –10), without changing
renal responses to hyperosmolality. The results suggest that inhib itory mechanisms dependent on cNTS/A2 neurons reduce water
intake and vasopressin-dependent pressor response to an acute
increase in plasma osmolality.
Descrição
Palavras-chave
c-Fos expression, Osmoreceptor, Blood pressure, Vasopressin, Thirst
Citação
FREIRIA-OLIVEIRA, Andre H. et al. Catecholaminergic neurons in the comissural region of the nucleus of the solitary tract modulate hyperosmolality-induced responses. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Rockville, v. 309, n. 9, p. R1082-R1091, 2015.