title: Selective C1 Lesioning Slightly Decreases Angiotensin II Type I Receptor Expression in the Rat Rostral Ventrolateral Medulla (RVLM).
abstract: Cardiovascular homeostasis is regulated in large part by the rostral ventrolateral medulla (RVLM) in mammals. Projections from the RVLM to the intermediolateral column of the thoracolumbar spinal cord innervate preganglionic neurons of the sympathetic nervous system causing elevation of blood pressure and heart rate. A large proportion, but not all, of the neurons in the RVLM contain the enzymes necessary for the production of epinephrine and are identified as the C1 cell group. Angiotensin II (Ang II) activates the RVLM acting upon AT1 receptors. To assess the proportion of AT1 receptors that are located on C1 neurons in the rat RVLM this study employed an antibody to dopamine-beta-hydroxylase conjugated to saporin, to selectively destroy C1 neurons in the RVLM. Expression of tyrosine hydroxylase immunoreactive neurons in the RVLM was reduced by 57 % in the toxin injected RVLM compared to the contralateral RVLM. In contrast, densitometric analysis of autoradiographic images of (125)I-sarcosine(1), isoleucine(8) Ang II binding to AT1 receptors of the injected side RVLM revealed a small (10 %) reduction in AT1-receptor expression compared to the contralateral RVLM. These results suggest that the majority of AT1 receptors in the rat RVLM are located on non-C1 neurons or glia.
authors.affiliation: Mississippi College, 200 S Capitol St, Clinton, MS, 39058, USA. eabourassa@mc.edu.|Department of Pharmacology, School of Pharmacy, University of Mississippi, Oxford, MS, 38677, USA. eabourassa@mc.edu.
authors.forename: Erick A
authors.initials: EA
authors.lastname: Bourassa
authors.affiliation: Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
authors.forename: Kristen A
authors.initials: KA
authors.lastname: Stedenfeld
authors.affiliation: Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15260, USA. Sved@pitt.edu.
authors.forename: Alan F
authors.initials: AF
authors.lastname: Sved
authors.affiliation: Department of Pharmacology, School of Pharmacy, University of Mississippi, Oxford, MS, 38677, USA. rs1251@nova.edu.|College of Pharmacy, Nova Southeastern University, 3200 S. University Dr., Fort Lauderdale, FL, 33328, USA. rs1251@nova.edu.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Speth
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D044140:Receptor, Angiotensin, Type 1; D000804:Angiotensin II; D014446:Tyrosine 3-Monooxygenase
keywords: AT1 angiotensin; C1 adrenergic neurons; RVLM; Radioligand binding; Rat brain; Receptor autoradiography; Receptors; Rostral ventrolateral medulla