[Physiological mechanisms of cardiovascular adaptation to orthostatism. Role of the sympathetic nervous system and pharmacological implications].
The main physiological adaptative systems occurring during orthostatism are discussed. The nervous mechanisms and especially baroreceptor pathways allow a rapid adaptation to the new hemodynamic conditions whereas hormones (mainly vasopressin) are involved later. The role of baroreflex and cardiocirculatory mechanisms is explained by the description of adaptative mechanisms in giraffe, an animal with its brain so far above the ground. The changes in adrenoceptor receptivity and the adaptative homeostatic mechanisms of the autonomic nervous system during orthostatism in human are discussed. Their characterization might allow to propose new pharmacological approaches for the treatment of orthostatic hypotension.
Montastruc
J L
JL
Laboratoire de Pharmacologie Médicale et Clinique, INSERM U 317, Faculté de Médecine, Toulouse.
Senard
J M
JM
Verwaerde
P
P
Montastruc
P
P
D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007024:Hypotension, Orthostatic / Q000188:drug therapy / Q000503:physiopathology; D011187:Posture; D011941:Receptors, Adrenergic / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology*
D011941:Receptors, Adrenergic
Mécanismes physiologiques de l'adaptation cardiovasculaire à l'orthostatisme. Rôle du système nerveux végétatif et implications pharmacologiques.