Effects of bilateral vestibular lesions on orthostatic  tolerance in awake cats

Jian, Brian J.; Cotter, Lucy A; Emanuel, Benjamin; Cass, Stephen P.; Yates, Bill J

doi:10.1152/jappl.1999.86.5.1552

Cited by 111 publications

(112 citation statements)

References 18 publications

(19 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, only 3 neurons with graviceptive responses that were best activated by pitch rotations were detected in this study. This observation is curious considering that the CVN participate in correcting disturbances in blood pressure and breathing elicited by sustained head-up pitch of the body (Uchino et al 1970;Yates et al 1993;Woodring et al 1997;Kerman and Yates 1998;Jian et al 1999;Cotter et al 2001;Cotter et al 2004;Wilson et al 2006).…”

Section: Discussionmentioning

confidence: 99%

“…It is thus unclear whether these alterations in vestibular nucleus neuronal activity elicited by postural changes in animals lacking labyrinthine inputs have functional significance. Previous studies showed that lesions of the CVN result in long-lasting or permanent impairments in adjusting blood pressure during postural alterations (Mori et al 2005), whereas the effects of a bilateral vestibular neurectomy on cardiovascular control dissipate within a week (Jian et al 1999), suggesting that integrity of the CVN is essential for adequate autonomic responses during movement. However, the present data do not address whether modulation of the activity of CVN neurons during changes in body position is essential for these responses to occur.…”

Section: Discussionmentioning

confidence: 99%

“…In conscious cats, compensatory adjustments in blood distribution in the body (Jian et al 1999;Wilson et al 2006) and respiratory muscle activity (Cotter et al 2001;Cotter et al 2004) during sustained 60° head-up pitch rotations are attenuated following a bilateral labyrinthectomy. Since the CVN mediate vestibular influences on autonomic regulation, these data suggest that a large fraction of neurons in this region should receive otolith organ inputs elicited by rotations in the pitch plane.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Responses of caudal vestibular nucleus neurons of conscious cats to rotations in vertical planes, before and after a bilateral vestibular neurectomy

et al. 2008

Self Cite

View full text Add to dashboard Cite

Although many previous experiments have considered the responses of vestibular nucleus neurons to rotations and translations of the head, little data are available regarding cells in the caudalmost portions of the vestibular nuclei (CVN), which mediate vestibulo-autonomic responses among other functions. This study examined the responses of CVN neurons of conscious cats to rotations in vertical planes, both before and after a bilateral vestibular neurectomy. None of the units included in the data sample had eye movement-related activity. In labyrinth-intact animals, some CVN neurons (22%) exhibited graviceptive responses consistent with inputs from otolith organs, but most (55%) had dynamic responses with phases synchronized with stimulus velocity. Furthermore, the large majority of CVN neurons had response vector orientations that were aligned either near the roll or vertical canal planes, and only 18% of cells were preferentially activated by pitch rotations. Sustained head-up rotations of the body provide challenges to the cardiovascular system and breathing, and thus the response dynamics of the large majority of CVN neurons were dissimilar to those of posturally-related autonomic reflexes. These data suggest that vestibular influences on autonomic control mediated by the CVN are more complex than previously envisioned, and likely involve considerable processing and integration of signals by brainstem regions involved in cardiovascular and respiratory regulation. Following a bilateral vestibular neurectomy, CVN neurons regained spontaneous activity within 24 h, and a very few neurons (<10%) responded to vertical tilts <15° in amplitude. These findings indicate that nonlabyrinthine inputs are likely important in sustaining the activity of CVN neurons; thus, these inputs may play a role in functional recovery following peripheral vestibular lesions.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Responses of caudal vestibular nucleus neurons of conscious cats to rotations in vertical planes, before and after a bilateral vestibular neurectomy

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…BPD infants presented with greater intersubject variability in BP responses to head-up tilt than controls. Vestibular dysfunction is expected to result in greater variability in BP during postural changes (10). Therefore, the increased variability in the present study likely results from the dysfunction of vestibulo-mediated cardiovascular control observed, instead of altered baroreflex function.…”

Section: Discussionmentioning

confidence: 71%

“…The dysfunction results in greater variability in BP control during postural changes (10). Similarly, increased BP variability has been observed in tilt tests performed in infants who have suffered from apparent life-threatening events (ALTEs) (11,12), further supporting the idea of vestibular dysfunction in SIDS.…”

mentioning

confidence: 77%

Altered Cardiovascular Control in Preterm Infants with Bronchopulmonary Dysplasia

et al. 2007

View full text Add to dashboard Cite

Vestibulo-mediated cardiovascular control in hazardous situations is important. Our hypothesis is that the prerequisite for sudden infant death syndrome (SIDS) is impaired vestibulo-mediated cardiovascular control. Prematurity is a risk factor for SIDS, and postnatal intermittent hypoxia may contribute to this risk. We studied heart rate (HR) and blood pressure (BP) responses in 10 infants with bronchopulmonary dysplasia (BPD) who were born at 27 Ϯ 2.4 (23-30) wk of gestation. Twenty healthy term infants served as controls. Cardiovascular tests were performed under polysomnographic control during slow-wave sleep (SWS) at a corrected age of 12 Ϯ 3.5 (7-19) wk. Control infants showed biphasic HR and BP responses to side motion with an immediate increase followed by a modest decrease and return to baseline. Compared with the controls, half of the BPD infants had altered BP responses (p Ͻ 0.005) without an early increase, followed by a more prominent decrease in BP. BPD infants also presented with a greater variability in BP responses to head-up tilts than did the controls (p Ͻ 0.001). In conclusion, these findings suggest that some BPD infants have impaired vestibular sympathoreflex-mediated cardiovascular control. This dysfunction may become critical in life-threatening situations. V estibular and cerebellar dysfunction has been suggested to be part of the pathophysiology of SIDS (1). Cardiovascular control mediated by vestibular nuclei and the cerebellum are important in hazardous situations such as hypovolemic and endotoxin shock (2,3). More than 80% of SIDS victims have shown neuronal apoptosis in vestibular nuclei and nuclei of the tractus solitarii, which are involved in baroand vestibular sympathoreflexes (4). SIDS victims also present with abnormalities elsewhere in the vestibular sympathoreflex pathway (5-7).During normal daily living, vestibular sympathoreflex dysfunction is not expected to have a profound effect on cardiovascular control because several compensatory circuits are involved in control of HR and BP (8,9). The dysfunction results in greater variability in BP control during postural changes (10). Similarly, increased BP variability has been observed in tilt tests performed in infants who have suffered from apparent life-threatening events (ALTEs) (11,12), further supporting the idea of vestibular dysfunction in SIDS.Most SIDS victims have suffered from hypoxia for at least several hours before the lethal event (13). SIDS victims may also have suffered from hypoxia earlier in life for multiple reasons, including placental insufficiency (14), intrauterine nicotine exposure (15), low or very low birth weight (16,17), hypoxia related to obstructive apnea events (18,19), or unfavorable head position during sleep (20,21). Our hypothesis is that hypoxic episodes cause a dysfunction in vestibulo-mediated cardiovascular control, thus making the infant more liable to die in life-threatening situations. To test the possible effects of hypoxia and test our hypothesis, we previously studied infan...

show abstract

Vestibular neurons in the rat contain imidazoleacetic acid‐ribotide, a putative neurotransmitter involved in blood pressure regulation

Martinelli¹,

Friedrich²,

Prell³

et al. 2007

J of Comparative Neurology

View full text Add to dashboard Cite

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.

show abstract

Effects of bilateral vestibular lesions on orthostatic tolerance in awake cats

Cited by 111 publications

References 18 publications

Responses of caudal vestibular nucleus neurons of conscious cats to rotations in vertical planes, before and after a bilateral vestibular neurectomy

Responses of caudal vestibular nucleus neurons of conscious cats to rotations in vertical planes, before and after a bilateral vestibular neurectomy

Altered Cardiovascular Control in Preterm Infants with Bronchopulmonary Dysplasia

Vestibular neurons in the rat contain imidazoleacetic acid‐ribotide, a putative neurotransmitter involved in blood pressure regulation

Contact Info

Product

Resources

About