TY - JOUR
T1 - Relative importance of sympathetic nerves and of circulating adrenaline and vasopressin in mediating hypertension after lesions of the caudal ventrolateral medulla in the rat
AU - Minson, Jane
AU - Chalmers, John
AU - Kapoor, Vimal
AU - Cain, Michael
AU - Caon, Adriana
PY - 1986/6
Y1 - 1986/6
N2 - Electrolytic lesions of the A1 noradrenaline cells in the caudal ventrolateral medulla cause transient hypertension and bradycardia in the conscious rat, as previously described in the rabbit. The lesions produced 100-fold increases in plasma arginine vasopressin, 40-fold increases in plasma adrenaline and fourfold increases in plasma noradrenaline levels. Absence of circulating vasopressin [homozygous diabetes insipidus rats (DI)] or circulating adrenaline (adrenalectomized rats) did not affect A1 hypertension, but sympathectomy with systemic 6-hydroxydopamine (6-OHDA) significantly attenuated A1 hypertension. A factorial experiment was performed to assess the relative contributions of these three peripheral effector mechanisms in a quantitative manner, with combined deficiencies of any two or of all three of these effector systems. Results suggest A1 hypertension in the rat to be primarily mediated through increased sympatho-adrenal activity. The largest component of hypertension (66%) results from increased sympathetic vasoconstrictor nerve activity, and a smaller part (34%) reflects the action of circulating adrenaline. Increases in vasopressin levels do not contribute to A1 hypertension, although vasopressin makes a major contribution to A1 lesion bradycardia.
AB - Electrolytic lesions of the A1 noradrenaline cells in the caudal ventrolateral medulla cause transient hypertension and bradycardia in the conscious rat, as previously described in the rabbit. The lesions produced 100-fold increases in plasma arginine vasopressin, 40-fold increases in plasma adrenaline and fourfold increases in plasma noradrenaline levels. Absence of circulating vasopressin [homozygous diabetes insipidus rats (DI)] or circulating adrenaline (adrenalectomized rats) did not affect A1 hypertension, but sympathectomy with systemic 6-hydroxydopamine (6-OHDA) significantly attenuated A1 hypertension. A factorial experiment was performed to assess the relative contributions of these three peripheral effector mechanisms in a quantitative manner, with combined deficiencies of any two or of all three of these effector systems. Results suggest A1 hypertension in the rat to be primarily mediated through increased sympatho-adrenal activity. The largest component of hypertension (66%) results from increased sympathetic vasoconstrictor nerve activity, and a smaller part (34%) reflects the action of circulating adrenaline. Increases in vasopressin levels do not contribute to A1 hypertension, although vasopressin makes a major contribution to A1 lesion bradycardia.
KW - 6-hydroxydopamine
KW - Adrenaline
KW - Central noradrenaline neurons
KW - Hypertension
KW - Sympathetic vasoconstrictor nerves
KW - Vasopressin
KW - Ventrolateral medulla
UR - http://www.scopus.com/inward/record.url?scp=0022449497&partnerID=8YFLogxK
U2 - 10.1097/00004872-198606000-00004
DO - 10.1097/00004872-198606000-00004
M3 - Article
C2 - 3090138
AN - SCOPUS:0022449497
VL - 4
SP - 273
EP - 281
JO - Journal of hypertension. Supplement : official journal of the International Society of Hypertension
JF - Journal of hypertension. Supplement : official journal of the International Society of Hypertension
SN - 0952-1178
IS - 3
ER -