Rostral ventrolateral medulla catechol involvement upon sino-aortic deafferentation: an in vivo voltammetric study.
Pharmacologically-induced hypertension engages few aminergic ventrolateral medullary cells. To further address this issue, reflex hypertension evoked by acute sino-aortic deafferentation was chosen as a model. Adrenergic rostral ventrolateral neurons were recorded with a continuous, catechol-specific tool, i.e. in vivo voltammetry. Controlled hypotension led to the expected increase in catechol signal in sham rats (n = 4) but not in deafferented (vagi, superior laryngeal and glossopharyngeal nerves) rats (n = 5). Thus, the central responsiveness to known stimuli remained intact in this preparation following acute sino-aortic deafferentation. However, acute sino-aortic deafferentation itself induced no increase in catechol signal (n = 4 or 5 respectively). No increase in catechol signal was, observed when deafferentation was performed a) under hyperoxic conditions (O2 = 100%, n = 5) b) by extensive deafferentation involving also the cervical sympathetic trunk under halothane (n = 5) c) upon restrictive deafferentation leaving the vagi intact under pentobarbital (n = 5) d) in decerebrate animals (n = 4). Adrenergic rostral ventrolateral medullary barosensitive bulbospinal neurons may be primarily involved during hypotension.
Rentero
N
N
Physiology, School of Medicine, Lyon, France.
Bruandet
N
N
Quintin
L
L
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D017704:Baroreflex / Q000502:physiology; D002396:Catechols / Q000378:metabolism*; D003714:Denervation; D004195:Disease Models, Animal; D004594:Electrophysiology; D006329:Heart Conduction System / Q000502:physiology / Q000601:surgery; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D008526:Medulla Oblongata / Q000473:pathology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D002396:Catechols