Alterations in circulating levels and cardiovascular tissue content of neuropeptide Y-like immunoreactivity during the development of deoxycorticosterone acetate-salt hypertension in the rat.
OBJECTIVE
To investigate the modification of plasma and tissue neuropeptide Y-like immunoreactivity (NPY-li) concentrations, in relation to blood pressure and plasma catecholamine levels, during the development of deoxycorticosterone acetate (DOCA)-salt hypertension.


METHODS
Mean arterial pressure (MAP), heart rate, tissue and plasma NPY-li levels, and aortic norepinephrine and epinephrine plasma levels were measured in conscious DOCA-salt hypertensive rats treated for 1, 2 and 3 weeks, and in their respective normotensive controls.


RESULTS
Both norepinephrine and NPY-li plasma levels increased significantly in parallel with blood pressure during DOCA-salt treatment, so that MAP was significantly correlated with plasma norepinephrine and NPY-li levels in hypertensive rats. Plasma NPY-li levels were also correlated with norepinephrine levels only in hypertensive rats, but were correlated with epinephrine levels only in normotensive animals. Tissue NPY-li content was lower in the mesenteric artery and heart ventricles after 1-3 weeks of DOCA-salt treatment, but the content in the adrenal gland was not significantly different from that in normotensive rats.


CONCLUSIONS
In DOCA-salt hypertensive rats, increased plasma NPY-li levels originate primarily from the sympathetic nerves, since those levels were correlated exclusively with circulating norepinephrine levels and they were associated with a reduction in NPY-li content of the heart and mesenteric artery. It is thus possible that the enhanced release of NPY-li from sympathetic nerves could contribute to the rise in blood pressure and to the maintenance of hypertension in this experimental model.
Moreau
P
P
Groupe de Recherche sur le système nerveux autonome, Faculty of Pharmacy, Université de Montréal, Québec, Canada.
de Champlain
J
J
Yamaguchi
N
N
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D003900:Desoxycorticosterone / Q000009:adverse effects; D006973:Hypertension / Q000209:etiology / Q000378:metabolism*; D008297:Male; D009478:Neuropeptide Y / Q000378:metabolism* / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism / Q000502:physiology; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012982:Sodium, Dietary / Q000009:adverse effects*; D013564:Sympathetic Nervous System / Q000378:metabolism
D009478:Neuropeptide Y; D012982:Sodium, Dietary; D003900:Desoxycorticosterone; D009638:Norepinephrine