PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Neural Pathways”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Interrupting neural pathways that transduce stressful information into physiological responses.

Stressor-stimuli evoke a noradrenergic process in the frontal lobes, the amplitude of which depends on both the individual's experience with the stimulus and his or her genetic background. Novel and noxious stimuli evoke large frontocortical responses and benign ones evoke relatively larger reactions in persons with a family history of cardiovascular disease. Blockade of neural projections from the frontal cortex and amygdala to the brainstem cardiovascular centers will normalize blood-pressure elevations in experimental hypertension and prevent lethal arrhythmias in animals with a myocardial infarction. The anti-mortality effect of the cardiac drugs known as beta-blockers is exerted by inhibition of cerebral beta-receptors, not peripheral ones. A new putative neuropeptide, NLX, may have the same desirable cardiovascular effects, but without the side-effects that limit clinical usefulness. The neural regulation of the heart during stress can be detected by a new deterministic measure of low-dimensional chaos in heartbeat intervals. In both animals and humans undergoing myocardial infarction, this deterministic measure correctly predicts lethal arrhythmogenesis, minutes to hours prior to the event. Thus an approach combining both brain and heart studies (i.e., "neurocardiology") has led to an understanding of how stressor-stimuli evoke autonomic reactions. This, in turn, has led to new methods in the diagnosis and treatment of cardiovascular disorders.

Animals↗
PubMed1985

Evidence for corticotropin-releasing factor, neurotensin, and somatostatin in the neural pathway from the central nucleus of the amygdala to the parabrachial nucleus.

The central nucleus of the amygdala (CNA) and the parabrachial nucleus of the pons (PBN) are included within a group of brain nuclei involved in autonomic responses. Previous studies have shown that the CNA sends a considerable projection to the PBN and that both nuclei contain neurons immunoreactive to many different peptides. In the present study, we used the combined retrograde fluorescence-immunofluorescence method to determine whether the CNA projection to the PBN contains any of the following neuropeptides: corticotropin-releasing factor (CRF), neurotensin (NT), somatostatin (SS), and enkephalin (ENK). Following injections of fluorescent dye into the PBN, neurons within both lateral and medial subdivisions of the CNA were retrogradely labeled. A significant percentage of CRF (54-66%)-, NT (40-53%)-, and SS (31-50%)-immunoreactive neurons were retrogradely labeled, predominantly within the lateral CNA. Enkephalin-immunoreactive neurons were never retrogradely labeled, although they were often found adjacent to retrogradely labeled neurons. Our results show that the lateral CNA is a major source of CRF, NT, and SS terminals within the PBN. Neurons in the medial CNA also provide a significant contribution to the CNA-PBN pathway, but their chemical nature remains to be determined. We conclude that CRF, NT, and SS are important putative neurotransmitters in the CNA's regulation of PBN function. This CNA-PBN peptidergic pathway may participate in stress-related cardiovascular and respiratory responses.

Amygdala↗
PubMed1992

Poliovirus spreads from muscle to the central nervous system by neural pathways.

A transgenic mouse model was used to address an unsolved question in the pathogenesis of poliomyelitis: how poliovirus invades the central nervous system (CNS). LD50 values for intramuscular and intracerebral inoculation of poliovirus in transgenic mice expressing poliovirus receptors (TgPVR mice) were similar. After intramuscular inoculation with poliovirus, paralysis was observed first in the inoculated limb. In contrast, localization of initial paralysis to the inoculated limb was not observed in normal mice inoculated intramuscularly with the mouse-adapted P2/Lansing poliovirus strain. After intramuscular inoculation, infectious poliovirus was first detected in the inferior segment of the spinal cord, then in the superior spinal cord and the brain. Sciatic nerve transection blocked poliovirus spread to the spinal cord after inoculation into the hindlimb footpad of TgPVR mice. These results demonstrate that in TgPVR mice, poliovirus spreads from muscle to the CNS through nerve pathways and that expression of the poliovirus receptor plays an important role in viral spread by this route.

Animals↗
PubMed1984

An HRP study of neural pathways to neocortical olfactory areas in monkeys.

Afferent fiber projections to the two orbitofrontal olfactory areas of monkeys were studied using the horseradish peroxidase (HRP) technique. After injections of HRP into the lateroposterior (LPOF) or centroposterior (CPOF) area of the orbitofrontal cortex, some differences were found in the distribution of labeled cells between the projections to the LPOF and CPOF. These results, along with those of previous electrophysiological investigations, suggest the following conclusions: (1) the extrathalamic olfactory pathway to the LPOF identified by Tanabe et al. has relay neurons primarily in the substantia innominata and the amygdala and, secondarily, in the prorhinal cortex and the hypothalamus; (2) direct fibers to the LPOF from the amygdala and the prorhinal cortex pass through the areas ventral to the thalamus; (3) the transthalamic olfactory pathway to the CPOF identified by Yarita et al. has relay neurons concentrated primarily in the magnocellular portion of the mediodorsal nucleus of the thalamus.

Animals↗
PubMed1978

[Neural pathway of Powassan virus spread in the central nervous system of white mice].

Electron microscopic investigation of the brains and lumbar spinal cords of adult albino mice infected with Powassan virus was carried out. Virus particles were found within all parts of neurons (perikarya, dendrites, axon), as well as within synaptic apparatus and intercellular gaps of the central nervous tissue. The possibility of the virus spread both throughout the cytoplasm of nerve cells and their processes and the extracellular spaces of the brain was confirmed. Localization of virions within neurons, synapses and myelinated fibers of the spinal cord after intracerebral inoculation suggests that virus spread in the CNS can occur through the CNS parenchyma and also through the nervous conduction pathways. The possible mechanisms of virus dissemination in the CNS of albino mice with experimental Powassan virus encephalomyelitis are discussed.

Animals↗
PubMed1985

Influence of neural pathways on the pyrexial response to surgical trauma.

Epidural analgesia inhibits several metabolic effects of trauma. Some of these effects are generated by the endogenous fever mediator interleukin-1. Postoperative fever was therefore studied in 52 patients, 25 of whom had had epidural analgesia and 27 general anaesthesia. Transvesical prostatectomy was used as standard surgical trauma. Most of the patients had postoperative temperature rise exceeding 0.5 degree C, but the rise was not influenced by epidural analgesia. These data suggest that the release of endogenous fever mediator is not under control of afferent pathways from the region of trauma. The findings are also consistent with regulation of interleukin-1 release which is independent of adrenal stimulation, cyclic AMP or beta-endorphin, as epidural analgesia prevents postoperative increase of these hormones.

Aged↗
PubMed1980

Lack of modulation of pituitary hormone stress response by neural pathways involving opiate receptors.

To evaluate the role of the opiate-like peptidergic pathways in modulating the pituitary hormone response to stress, we measured the GH, PRL, and cortisol responses to hypoglycemia and exercise in normal subjects with and without pretreatment with naloxone, given in the centrally active dose of 0.4 mg iv. Basal serum levels of GH, PRL, and cortisol were not changed significantly by prior naloxone administration. The maximum incremental response of GH to exercise was significantly blunted (13.1 +/- 1.6 vs. 6.0 +/- 1.4; P less than 0.001) by prior naloxone administration. Pretreatment with naloxone did not affect the responses of GH, PRL, or cortisol to hypoglycemia or the PRL response to L-dopa. On the basis of these studies we conclude that the opiate-like peptidergic pathways are not important in the regulation of basal levels of GH, PRL, and cortisol and have only a modest modulating influence on the stress-induced release of the hormones, which may be obscured in the face of severe stress.

Female↗
PubMed1982

Neural pathways to lower urinary tract identified by retrograde axonal transport of horseradish peroxidase.

A new technique for tracing nerve fibers supplying specific organs by retrograde axonal transport of the enzyme horseradish peroxidase (HRP) was used to determine the innervation of various segments of the lower urinary tract. HRP was injected at the level of the bladder neck, postprostatic urethral segment, pelvic nerve, pudendal nerve, and pelvic floor musculature to determine precise nerve supply to each site, as well as possible overlap. The technique determines the exact spinal level of innervation, as well as the number of nuclei directly related to the motor neuron axons supplying innervation to each particular site. Representation of these nuclei at various levels of the spinal cord was shown in various serial sections obtained after the injection of HRP. This technique is accurate and precise; it is valuable in establishing exact neural anatomic connections between the central nervous system and target organs.

Anal Canal↗
PubMed1971

Neural pathways associated with hypothalamically elicited attach behavior in cats.

Small electrolytic lesions were made in cats through electrodes, which, when stimulated, elicited either quiet biting attack or affective paw strike attack upon rats. The Nauta method for impregnating degenerating axoplasm was used to reveal that degeneration resulting from lesions at quiet attack sites followed largely along the course of the medial forebrain bundle, while the degeneration after lesions of affective attack sites was concentrated more heavily in the periventricular system.

Aggression↗
PubMed1974

Neural pathways from thalamus associated with regulation of aggressive behavior.

Small electrolytic lesions were made through electrodes in the thalamus of cats at sites where electrical stimulation elicited attack on a rat. Staining by modified Nauta reduced silver methods revealed that significant degeneration passed caudally from the lesions and entered the midbrain dorsal central gray region. Electrical stimulation of this dorsal midbrain region elicited attack on a rat, and destruction of this region suppressed the attack elicited by thalamic stimulation.

Aggression↗
PubMed1975

Mapping of functional neural pathways by autoradiographic survey of local metabolic rate with (14C)deoxyglucose.

An enzymatic preparation from human brain converts tryptamine to tryptoline (9H-1,2,3,4-tetrahydropyrido(3,4-b)indole) in the presence of 5-methyltetrahydrofolic acid. Similarly, N-methyltryptamine and 5-hydroxytryptamine yield 1-methyltryptoline and 5-hydroxytryptoline, respectively. Neither in vitro nor in vivo formation of these compounds by human tissues has been described.

Animals↗
PubMed1985

Neural pathways mediating the corneal blink reflex and Bell's phenomenon in the cat.

Two central projections from the corneal representation of the sensory trigeminal complex in the cat were demonstrated with horseradish peroxidase, autoradiographic and Golgi methods: (1) to the dorsal subdivision of the ipsilateral facial nucleus that innervates the orbicularis oculi muscle; and (2) to the bordering area between the contralateral central gray matter and the oculomotor nucleus, which receives dendrites of the oculomotor cells innervating the contralateral superior rectus muscle. These two routes probably mediate early responses of the corneal blink reflex and Bell's phenomenon, respectively.

Animals↗