TY - JOUR
T1 - Vestibular neurons in the rat contain imidazoleacetic acid-ribotide, a putative neurotransmitter involved in blood pressure regulation
AU - Martinelli, Giorgio P.
AU - Friedrich, Victor L.
AU - Prell, George D.
AU - Holstein, Gay R.
N1 - Funding Information:
Our studies in Oman began after Bob Coleman introduced us to this exceptional ophiolite in 1979. It is a pleasure to acknowledge him for his generous support to the entire community interested in oceanic lithospheric processes. Field campaigns were conducted thanks to the hospitality of the people and authorities of Oman, and particularly the Ministry of Commerce and Industry. Financial support was received from the Centre National de la Recherche Scientifique, from the Institut Universi-taire de France, and from the French Embassy in Muscat. Reviews by Nikolas Christensen and Javier Escartin have substantially improved the manuscript.
PY - 2007/4/1
Y1 - 2007/4/1
N2 - A substantial body of research has led to the recognition that the vestibular system participates in blood pressure modulation during active movements and changes in posture, and that this modulation is effected at least partly by the caudal vestibular nuclei. The I-4 isomer of imidazoleacetic acid-ribotide (IAA-RP) is a putative neurotransmitter/modulator that is thought to be an endogenous regulator of general sympathetic drive, particularly systemic blood pressure. The present study employed immunofluorescence and light and electron microscopic immunocytochemistry to visualize IAA-RP in the vestibular nuclei of adult male rats. The results demonstrate IAA-RP immunolabeling of subpopulations of vestibular neurons in the descending nucleus and the caudal half of the medial nucleus, with scattered immunostained vestibular neurons also present more rostrally. On the basis of double immunofluorescence staining for IAA-RP and calbindin, many of these ribotide-immunoreactive neurons appear to be innervated by cerebellar Purkinje cell afferents. Ultrastructural observations in the caudal vestibular nuclei confirm the IAA-RP immunolocalization in cell bodies and dendritic processes, and in some myelinated axons and presynaptic boutons. The regional distribution of IAA-RP immunoreactivity corresponds to the location of vestibular neurons involved in autonomic functions. The presence of IAA-RP in those neurons suggests that they participate specifically in vestibulo-autonomic regulation of blood pressure. The localization of immunostain in processes and terminals suggests that vestibulo-autonomic activity is subject to local feedback control. Overall, the observations offer a chemoanatomic basis for understanding the vestibular side effects commonly experienced by patients treated with clonidine and other imidazoline-related drugs.
AB - A substantial body of research has led to the recognition that the vestibular system participates in blood pressure modulation during active movements and changes in posture, and that this modulation is effected at least partly by the caudal vestibular nuclei. The I-4 isomer of imidazoleacetic acid-ribotide (IAA-RP) is a putative neurotransmitter/modulator that is thought to be an endogenous regulator of general sympathetic drive, particularly systemic blood pressure. The present study employed immunofluorescence and light and electron microscopic immunocytochemistry to visualize IAA-RP in the vestibular nuclei of adult male rats. The results demonstrate IAA-RP immunolabeling of subpopulations of vestibular neurons in the descending nucleus and the caudal half of the medial nucleus, with scattered immunostained vestibular neurons also present more rostrally. On the basis of double immunofluorescence staining for IAA-RP and calbindin, many of these ribotide-immunoreactive neurons appear to be innervated by cerebellar Purkinje cell afferents. Ultrastructural observations in the caudal vestibular nuclei confirm the IAA-RP immunolocalization in cell bodies and dendritic processes, and in some myelinated axons and presynaptic boutons. The regional distribution of IAA-RP immunoreactivity corresponds to the location of vestibular neurons involved in autonomic functions. The presence of IAA-RP in those neurons suggests that they participate specifically in vestibulo-autonomic regulation of blood pressure. The localization of immunostain in processes and terminals suggests that vestibulo-autonomic activity is subject to local feedback control. Overall, the observations offer a chemoanatomic basis for understanding the vestibular side effects commonly experienced by patients treated with clonidine and other imidazoline-related drugs.
KW - Adrenergic receptors
KW - Autonomic nervous system
KW - Cardiovascular regulation
KW - Imidazol(in)e receptors
KW - Vestibulo-sympathetic reflex
UR - http://www.scopus.com/inward/record.url?scp=34247232163&partnerID=8YFLogxK
U2 - 10.1002/cne.21271
DO - 10.1002/cne.21271
M3 - Article
C2 - 17278132
AN - SCOPUS:34247232163
SN - 0021-9967
VL - 501
SP - 568
EP - 581
JO - Journal of Comparative Neurology
JF - Journal of Comparative Neurology
IS - 4
ER -