A horseradish peroxidase investigation of carotid sinus nerve components in the rat

doi:10.1016/0304-3940(84)90191-5

Neuroscience Letters

Volume 46, Issue 1, 20 April 1984, Pages 13-18

https://doi.org/10.1016/0304-3940(84)90191-5 Get rights and content

Abstract

The brainstem location of afferent and efferent components in rat carotid sinus nerve (CSN) was determined by transecting the CSN and applying horseradish peroxidase. Afferent label was heaviest in the ipsilateral medial solitary nucleus (mNTS). Afferents were also found in the ipsilateral ventrolateral solitary nucleus, area postrema, and bilaterally in the commissural nucleus of the solitary complex. Efferent labeled cells were found in the ipsilateral rostral nucleus ambiguus and the inferior salivatory nucleus. The CSN afferents in the mNTS terminated rostral to neurons which project to the nucleus ambiguus thus implicating the existence of interneurons in the baroreceptor reflex pathway.

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Cited by (53)

Central Autonomic System
2015, The Rat Nervous System: Fourth Edition
The central autonomic system is defined by the cell groups that receive direct or disynaptically relayed input from the nucleus of the solitary tract, or that contribute projections to autonomic preganglionic neurons or their presynaptic inputs. The cell groups identified by these properties also project extensively among themselves, forming a true network. In this chapter, we identify the cell groups from the medulla and spinal cord through the brainstem, hypothalamus, thalamus, amygdala, and cortex that contribute to the central autonomic system. We then review the connections within the central autonomic network; the pathways that provide visceral sensory input to, and visceral motor output from the network; and the connections of the central autonomic system with cognitive, endocrine, and behavioral systems that must be integrated with autonomic responses. We also consider the neurotransmitters used by this network, and how they contribute to its functions.
Cannabinoid receptor 1 signaling in cardiovascular regulating nuclei in the brainstem
2014, Journal of Advanced Research
Citation Excerpt :
Upon stimulation, the NTS elicits a reduction in the BP, HR, and sympathetic outflow [53,54]. The most cardiovascular-relevant part of the NTS is located at the most caudal part of the NTS, which contains synapses from chemo and aortic baroreceptor processes that contact with secondary order neurons within the NTS [55,56]. The latter communicate either directly or indirectly through third order neurons with other nuclei including RVLM, hypothalamus or CVLM [57–60].
Cannabinoids elicit complex hemodynamic responses in experimental animals that involve both peripheral and central sites. Centrally administered cannabinoids have been shown to predominantly cause pressor response. However, very little is known about the mechanism of the cannabinoid receptor 1 (CB₁R)-centrally evoked pressor response. In this review, we provided an overview of the contemporary knowledge regarding the cannabinoids centrally elicited cardiovascular responses and the possible underlying signaling mechanisms. The current review focuses on the rostral ventrolateral medulla (RVLM) as the primary brainstem nucleus implicated in CB₁R-evoked pressor response.
Hemodynamic and respiratory responses to microinjection of ATP into the intermediate and caudal NTS of awake rats
2005, Brain Research
Citation Excerpt :
The nucleus tractus solitarii (NTS) is the site of integration of the viscerosensory information in the brainstem and it is involved mainly with cardiovascular and respiratory control. Several studies have shown that carotid body chemoreceptor afferents project to different subnuclei within the rostral and intermediate portions of the NTS and bilaterally to the commissural subnucleus of the caudal NTS [5–7,28]. There is evidence supporting the involvement of adenosine-5′-triphosphate (ATP) as an excitatory neurotransmitter released by afferent nerve terminals or interneurons in the NTS [11,12,24].
The nucleus tractus solitarii (NTS) is the site of integration of the peripheral chemoreceptor afferents in the brainstem. Previous studies from our laboratory have shown that microinjection of ATP into the intermediate NTS produced increases in arterial pressure and bradycardia. In the present study, we evaluated the hemodynamic and respiratory responses to microinjection of ATP into the intermediate and caudal commissural NTS. In the same group of rats the responses were compared with cardiorespiratory responses to chemoreflex activation (KCN, i.v.). The data show that microinjection of ATP into the intermediate NTS produced pressor and bradycardic responses similar to those observed in response to chemoreflex activation but apnoea instead of tachypnoea. Microinjection of ATP into caudal commissural NTS produced increase in arterial pressure and tachypnoea similar to the chemoreflex but a minor bradycardia. The data show that microinjection of ATP into different sub-regions of the NTS produces a diverse pattern of hemodynamic and respiratory responses and suggest the involvement of this purine in the neurotransmission of the cardiovascular reflex in the NTS.
Central Autonomic System
2004, The Rat Nervous System
Gene expression in autonomic areas of the medulla and the central nucleus of the amygdala in rats during and after space flight
2004, Neuroscience
During space flight astronauts show vestibular-related changes in balance, eye movements, and spontaneous and reflex control of cardiovascular, respiratory and gastrointestinal function, sometimes associated with space motion sickness. These symptoms undergo compensation over time. Here we used changes in the expression of two immediate-early gene (IEG) products to identify cellular and molecular changes occurring in autonomic brainstem regions of adult male albino rats killed at different times during the Neurolab Space Mission (STS-90). Both direct effects of gravitational changes, as well as indirect effects of gravitational changes on responses to light exposure were examined.
Regions under the direct control of vestibular afferents such as the area postrema and the caudal part of the nucleus of the tractus solitarius (NTSC) were both directly and indirectly affected by gravity changes. These areas showed no changes in the expression of IEG products during exposure to microgravity with respect to ground controls, but did show a significant increase 24 h after return to 1 G (gravity). Exposure to microgravity significantly inhibited gene responses to light exposure seen after return to 1 G. A similar direct and indirect response pattern was also shown by the central nucleus of the amygdala, a basal forebrain structure anatomically and functionally related to the NTS.
The rostral part of the NTS (NTSR) receives different afferent projections than the NTSC. This region did not show any direct gravity-related changes in IEG expression, but showed an indirect effect of gravity on IEG responses to light. A similar pattern was also obtained in the intermediate reticular nucleus and the parvocellular reticular nucleus. Two other medullary reticular structures, the dorsal and the ventral medullary reticular nuclei showed a less well defined pattern of responses that differed from those seen in the NTSC and NTSR.
The short- and long-lasting molecular changes in medullary and basal forebrain gene expression described here are thought to play an important role in the integration of autonomic and vestibular signals that ultimately regulate neural adaptations to space flight.
Effects of selective sinoaortic denervations on phenylephrine-induced activational responses in the nucleus of the solitary tract
2000, Neuroscience
Intravenous administration of phenylephrine provokes a pattern of cellular activation in the nucleus of the solitary tract that resembles the central distributions of primary baroreceptor afferents supplied by the carotid sinus and aortic depressor nerves. Transganglionic transport and denervation methods were used in an experimental setting to test the dependence of phenylephrine-induced Fos immunoreactivity on the integrity of buffer nerve afferents, and to identify the subregions of the nucleus of the solitary tract supplied by each. Cholera toxin B–horseradish peroxidase injections into either or both nerves revealed terminal labeling concentrated in, but not restricted to, the dorsal commissural part of the nucleus of the solitary tract at the level of the apex of calamus scriptorius, and extending into the dorsal subnucleus at the level of the area postrema. Preferential ramifications of carotid sinus and aortic depressor nerve afferents at the levels of the commissural part of the nucleus and the area postrema, respectively, were reflected in the extent to which labeled fibers comingled with neurons exhibiting phenylephrine-induced Fos in dual labeling experiments. Complete sinoaortic denervation reduced by 90% the number of neurons exhibiting drug-induced Fos expression. Selective carotid and aortic sinus denervations effected partial reductions manifest preferentially in the caudal and rostral foci of the distribution, respectively. Reduced activational responses at the level of the area postrema of aortic sinus-denervated rats were accompanied by a reduction in cellular nicotinamide adenine dinucleotide phosphate-diaphorase activity in this region. Animals killed 30 days after complete sinoaortic denervation displayed no evidence of recovery of phenylephrine-induced Fos, while the strength and distribution of the response in rats that received selective carotid sinus denervation were indistinguishable from those seen in controls.
These findings (i) support the dependence of phenylephrine-induced Fos expression on the integrity of carotid sinus and aortic depressor nerve afferents, (ii) provide anatomical and functional evidence that the two buffer nerves distribute differentially within the nucleus of the solitary tract, and (iii) implicate central reorganization as a likely basis for functional recovery of baroreflex mechanisms following partial sinoaortic denervation.

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A horseradish peroxidase investigation of carotid sinus nerve components in the rat

Abstract

Neurosci. Lett.

Neurosci. Lett.

J. auton. nerv. Syst.

Neurosci. Lett.

Brain, Res.

Brain Res.

Brain, Res.

Brainstem areas which project to cardiac regions of the nucleus ambiguus in rat

Soc. Neurosci. Abstr.

The central origin of efferent pathways in the carotid sinus nerve of the cat

Science