Lesion of the commissural nucleus of the solitary tract/A2 noradrenergic neurons facilitates the activation of angiotensinergic mechanisms in response to hemorrhage.
Neuroscience
; 254: 196-204, 2013 Dec 19.
Article
en En
| MEDLINE
| ID: mdl-24060823
In the present study, we investigated the effects of lesions of A2 neurons of the commissural nucleus of the solitary tract (cNTS) alone or combined with the blockade of angiotensinergic mechanisms on the recovery of arterial pressure (AP) to hemorrhage in conscious rats. Male Holtzman rats (280-320g) received an injection of anti-dopamine-beta-hydroxylase-saporin (12.6ng/60nl; cNTS/A2-lesion, n=28) or immunoglobulin G (IgG)-saporin (12.6ng/60nl, sham, n=24) into the cNTS and 15-21days later had a stainless steel cannula implanted in the lateral ventricle. After 6days, rats were submitted to hemorrhage (four blood withdrawals, 2ml/300g of body weight every 10min). Both cNTS/A2-lesioned and sham rats had similar hypotension to hemorrhage (-62±7 and -73±7mmHg, respectively), however cNTS/A2-lesioned rats rapidly recovered from hypotension (-5±3mmHg at 30min), whereas sham rats did not completely recover until the end of the recording (-20±3mmHg at 60min). Losartan (angiotensin type 1 receptor antagonist) injected intracerebroventricularly (100µg/1µl) or intravenously (i.v.) (10mg/kg of body weight) impaired the recovery of AP in cNTS/A2-lesioned rats (-24±6 and -35±7mmHg at 30min, respectively). In sham rats, only i.v. losartan affected the recovery of AP (-39±6mmHg at 60min). The results suggest that lesion of the A2 neurons in the cNTS facilitates the activation of the angiotensinergic pressor mechanisms in response to hemorrhage.
Palabras clave
6-OHDA; 6-hydroxydopamine; ANG II; ANG II type 1; AP; AT1; AT1 receptors; AV3V; HR; IgG; KCN; LV; MAP; NTS; PAP; PBS; PFA; PVN; SEM; SFO; SNP; SON; TH; VLM; angiotensin II; anteroventral third ventricle; arterial pressure; cNTS; catecholamine; commissural nucleus of the solitary tract; heart rate; iNTS; immunoglobulin G; intermediate nucleus of the solitary tract; lateral ventricle; losartan; mean arterial pressure; nucleus of the solitary tract; paraformaldehyde; paraventricular; phosphate buffer saline; potassium cyanide; pulsatile arterial pressure; sodium nitroprusside; standard error of means; subfornical organ; supraoptic nuclei; tyrosine hydroxylase; ventrolateral medulla
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Angiotensina II
/
Núcleo Solitario
/
Neuronas Adrenérgicas
/
Hemorragia
Límite:
Animals
Idioma:
En
Revista:
Neuroscience
Año:
2013
Tipo del documento:
Article
País de afiliación:
Brasil