The effect of yohimbine on sympathetic responsiveness in essential hypertension.
We have studied the sympathetic response to blockade of presynaptic alpha 2-adrenoceptors in essential hypertension by measuring plasma concentrations of noradrenaline after a single oral dose of yohimbine, an alpha 2-adrenoceptor antagonist. Mean baseline plasma noradrenaline and adrenaline concentrations were similar in the hypertensive and normotensive groups. Yohimbine (0.2 mg x kg-1 orally) caused a lesser increase in the plasma concentrations of noradrenaline in hypertensive patients (+67%) than in normotensive subjects (+178%) and a pressor response in hypertensive (but not in normotensive) patients. These results are consistent with an alteration in the balance of alpha-adrenoceptors (for example presynaptic alpha 2-adrenoceptor desensitization and post-synaptic alpha 1-adrenoceptor hyper-responsiveness) which would help to develop and/or maintain arterial hypertension.
Damase-Michel
C
C
Laboratoire de Pharmacologie Médicale et Clinique, INSERM, Toulouse, France.
Tran
M A
MA
Llau
M E
ME
Chollet
F
F
Senard
J M
JM
Guiraud-Chaumeil
B
B
Montastruc
J L
JL
Montastruc
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000187:drug effects; D002395:Catecholamines / Q000097:blood; D002940:Circadian Rhythm; D004837:Epinephrine / Q000097:blood; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology; D015016:Yohimbine / Q000494:pharmacology*
D002395:Catecholamines; D015016:Yohimbine; D009638:Norepinephrine; D004837:Epinephrine