Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Autonomic Pathways”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 1,135 records · Page 63Linked to original sources
PubMed1999

Immunohistochemical and morphometric investigations of the influence of botulinum toxin on the submandibular gland of the rat.

Immunohistochemical methods were used to study the effects of botulinum toxin A on the concentration of acetylcholinesterase in the submandibular gland of the rat. The toxin was injected into the glands of healthy adult female Wistar rats and immunohistochemistry performed on the excised organs. Morphometric measurements were also carried out to study changes of cell morphology after local applications of botulinum toxin A. Compared with untreated glands or glands injected with saline there was a decrease of acetylcholinesterase in the glands treated with botulinum toxin. As the cholinergic pathway of the autonomic nervous systems plays an important role in eliciting secretion from the salivary glands, inhibition of secretion by local application of botulinum toxin could be considered a therapeutic option for the treatment of various diseases affecting salivary gland function.

Animals↗
PubMed2000

The morphology of apoptosis.

The concept of apoptotic cell death as an essential part of the development and life of complex organisms has been devised in different situations and tested from various angles. This review article discusses the morphological changes during death by apoptosis. In cells undergoing apoptosis, an intracellular signalling pathway operates cell autonomously to implement the death and disposal of the cell. The similarity of the biochemical events during apoptosis in different situations is reflected by a high uniformity of morphological changes in many situations of naturally occurring or experimentally induced cell death. The unifying concept of apoptosis has been derived from the observation of this morphological consistency of dying cells almost 30 years ago. Since then, we have learned much about the intracellular signalling in the apoptotic process and the molecular background has been delineated which guides the initiation of the morphological changes. Here, an attempt is made to present the current knowledge about the molecular events in the development of these morphological alterations and to place these changes in the context of apoptotic cell death.

Animals↗
PubMed2004

Riluzole improves motor deficits and attenuates loss of striatal neurons in a sequential double lesion rat model of striatonigral degeneration (parkinson variant of multiple system atrophy).

We investigated neuroprotective effects of riluzole, an anti-glutamatergic agent that is FDA approved for disease-modifying therapy in amyotrophic lateral sclerosis (ALS), in an established double lesion rat model of striatonigral degeneration (SND), the neuropathological substrate of parkinsonism associated with MSA (MSA-P). Riluzole was administered prior to and consecutively for ten days following double lesion placement in the left-sided medial forebrain bundle and ipsilateral striatum. Assessment of motor behaviour using a flex field system showed a significant reduction of motor disturbance in animals with striatonigral lesions treated with riluzole compared to lesioned but untreated animals (P<0.001). DARPP-32 immunohistochemistry revealed a significant reduction of absolute striatal lesion volume in riluzole treated animals compared to lesioned but untreated animals (P<0.01). No significant difference in counts of nigral dopaminergic neurons was found in treated versus untreated double-lesioned animals. The results of our study indicate that riluzole mediates neuroprotective effects in the double lesion rat model of MSA-P. Whether riluzole also protects autonomic and cerebellar pathways that are frequently affected in MSA remains to be determined. Nonetheless, our study is the first to provide an experimental rationale for exploring possible neuroprotective effects of riluzole in MSA.

Animals↗
PubMed1983

Central cardiovascular action of penicillin in anaesthetized dogs and rats.

Penicillin (2-3 mg X kg-1) administered into the cisterna magna (i.c.) of dogs anaesthetized with alpha-chloralose induced a significant increase in mean blood pressure (MBP) and bradycardia, whereas intravenous injections of the same doses had negligible effects. Moreover, dogs receiving central injections of penicillin showed seizures abolished by administration of decamethonium bromide (100 micrograms X kg-1, i.v.). In urethane anaesthetized rats, intracerebroventricular (i.c.v.) injections of penicillin (0.3-3 mg X kg-1) caused dose-dependent increases in mean blood pressure while the intravenous route led to opposite effects. gamma-aminobutyric acid (GABA) (1 mg X kg-1), its agonist muscimol (2 micrograms X kg-1) and the alpha 2-adrenoceptor agonist clonidine (1 micrograms X kg-1) injected intracisternally induced hypotension and bradycardia in dogs. These effects were abolished in animals pretreated with penicillin. In rats, the same agents injected intraventricularly respectively at 0.5 mg X kg-1, 0.5 micrograms X kg-1 induced also hypotension. The effect of clonidine only, was antagonized by pretreatment with penicillin, while penicillin administered at the peak of the hypotensive effect caused by GABA or muscimol reversed it. It is suggested that penicillin acts centrally as a GABA-antagonist, and that the cardiovascular effects of clonidine seem to be mediated, at least in part, by the stimulation of a GABAergic pathway controlling the autonomic nervous system.

Adrenalectomy↗
PubMed1983

Central connections of the hepatic branch of the vagus nerve: a horseradish peroxidase histochemical study.

The hepatic branch of the vagus nerve has been implicated as an important source of afferent input controlling both physiological and behavioral homeostasis. In addition, it is clear that parasympathetic efferents to the liver can significantly alter hepatic functions. In order to begin physiological studies on the nature of hepatic afferent and efferent relations, it will be necessary to understand the central anatomical organization of the components of this small visceral nerve. By carefully exposing and dissecting the hepatic branch of the vagus and applying crystalline horseradish peroxidase (HRP) to it, we were able to elucidate a predominant pattern of afferent terminations within the left subnucleus gelatinosus, the medial division of the left solitary nucleus and the left lateral edge of the area postrema. Efferent nuclei were concentrated in the left dorsal motor nucleus of the vagus (DMN) with a few scattered neurons located in the right DMN as well as the left anterior nucleus ambiguous.

Afferent Pathways↗
PubMed1988

Neural pathways and pharmacological modulation of defecation reflex in rats.

1. A new method was developed for quantitative studies on defecation reflex in urethane-anesthetized rats which involves the continuous infusion of saline (0.1 ml/min) to distend a balloon placed in the rectum. At threshold values, the balloon was expelled during an active rectal contraction. 2. Balloon expulsion was greatly delayed or even abolished by i.v. hexamethonium. Cord transection at the upper cervical level increased defecation threshold but a functional, hexamethonium-sensitive response was still elicited in spinal rats. 3. Various parameters of the defecation response were modulated by drugs (phentolamine, picrotoxin, naloxone) expected to interfere (either centrally or peripherally), with neural pathways controlling the autonomic outflow for the reflex response. 4. In capsaicin-pretreated rats (50 mg/kg s.c. on 2nd day of life, experiments performed at 2 months), daily fecal production was unchanged as compared to vehicle-treated, age-matched controls. However, under urethane-anesthesia, defecation threshold was increased at higher-than-normal values by capsaicin-pretreatment. 5. In in vitro experiments, capsaicin (1 microM) induced a transient inhibition of field stimulation-induced contractions of the rat isolated rectum. This effect was mimicked by application of calcitonin gene-related peptide (CGRP) (0.1 microM) while Substance P (0.1 microM) had an opposite effect. In preparations desensitized to exogenous CGRP, the inhibitory effect of capsaicin was almost abolished. 6. These findings indicate that in rats, reflex defecation is mainly organized at spinal level, although the participation of supraspinal centers may modify the functional response. Capsaicin-sensitive afferents may be involved in the initiation of certain forms of reflex defecation, although capsaicin-resistant mechanisms are capable of activating the normal excretory function.

Animals↗
PubMed2006

Comparative localization of leucine-rich repeat-containing G-protein-coupled receptor-7 (RXFP1) mRNA and [33P]-relaxin binding sites in rat brain: restricted somatic co-expression a clue to relaxin action?

Relaxin is a polypeptide hormone with established actions associated with reproductive physiology, but until recently the precise nature of the relaxin receptor and its transmembrane signaling mechanisms had remained elusive. In 2002 however, the leucine-rich-repeat-containing G-protein-coupled receptor-7 (now classified as RXFP1) was identified as a cognate receptor for relaxin, with activation resulting in stimulation of intracellular cAMP production. These findings, along with the presence and putative actions of relaxin within the CNS and earlier descriptions of relaxin binding sites in brain, suggest the importance and feasibility of determining if these relaxin binding sites represent leucine-rich-repeat-containing G-protein-coupled receptor-7 and their precise comparative distribution. Thus, the current study reports the distribution of leucine-rich-repeat-containing G-protein-coupled receptor-7 mRNA throughout the rat brain using in situ hybridization histochemistry of [(35)S]-labeled oligonucleotides and the comparative distribution of [(33)P]-human relaxin binding sites. The extensive, topographical distribution of leucine-rich-repeat-containing G-protein-coupled receptor-7 mRNA throughout the adult rat brain correlated very closely to that of [(33)P]-relaxin binding sites. Leucine-rich-repeat-containing G-protein-coupled receptor-7 mRNA was expressed by neurons in several brain regions, including the olfactory bulb, cerebral cortex, thalamus, hippocampus, hypothalamus, midbrain, pons and medulla. Receptor transcripts were most abundant in areas such as the basolateral amygdala, subiculum, deep layers of the cingulate, somatosensory and motor cortices and intralaminar/midline thalamic nuclei. These areas also contained very high densities of [(33)P]-relaxin binding sites, suggesting a largely somatic localization of leucine-rich-repeat-containing G-protein-coupled receptor-7 protein and site of action for relaxin peptide. The central distribution of relaxin-producing neurons has been described, while data on the topography of nerve terminals that contain and secrete the peptide are currently lacking; but overall these findings strongly suggest that leucine-rich-repeat-containing G-protein-coupled receptor-7 is the cognate receptor for relaxin in the rat brain, and support a role for relaxin-leucine-rich-repeat-containing G-protein-coupled receptor-7 signaling in various somatosensory, autonomic and neurohumoral pathways, which warrants further investigation.

Animals↗
PubMed2006

Thermoregulatory behavior is disrupted in rats with lesions of the anteroventral third ventricular area (AV3V).

Core body temperature is maintained through a combination of physiological and behavioral effector mechanisms. While the neural pathways involved in autonomic responses to a heat stress are slowly being unraveled, those controlling behavioral responses have remained elusive. We have recently demonstrated that the tissue that surrounds the anteroventral third ventricular region (AV3V) has an important role in the autonomic response to a heat stress. The purpose of the present study was to determine the impact lesions of the AV3V have on naturally occurring thermoregulatory behaviors. Core temperature was elevated at a constant rate (0.03 degrees C/min) for 90 min using an infrared heat lamp. Animals were videotaped and scored throughout the heating protocol for grooming, escape jumps and postural extension. The frequency of escape jumps and adoption of an extended posture were significantly reduced in AV3V-lesion rats. In contrast, grooming behavior was unaffected by AV3V lesions, although heat-induced salivation was markedly attenuated. These results demonstrate that the AV3V region is pivotal in the regulation of both autonomic and behavioral thermoregulatory effector mechanisms.

Animals↗
PubMed2006

Metabolic sensing neurons and the control of energy homeostasis.

The brain and periphery carry on a constant conversation; the periphery informs the brain about its metabolic needs and the brain provides for these needs through its control of somatomotor, autonomic and neurohumoral pathways involved in energy intake, expenditure and storage. Metabolic sensing neurons are the integrators of a variety of metabolic, humoral and neural inputs from the periphery. Such neurons, originally called "glucosensing", also respond to fatty acids, hormones and metabolites from the periphery. They are integrated within neural pathways involved in the regulation of energy homeostasis. Unlike most neurons, they utilize glucose and other metabolites as signaling molecules to regulate their membrane potential and firing rate. For glucosensing neurons, glucokinase acts as the rate-limiting step in glucosensing while the pathways that mediate responses to metabolites like lactate, ketone bodies and fatty acids are less well characterized. Many metabolic sensing neurons also respond to insulin and leptin and other peripheral hormones and receive neural inputs from peripheral organs. Each set of afferent signals arrives with different temporal profiles and by different routes and these inputs are summated at the level of the membrane potential to produce a given neural firing pattern. In some obese individuals, the relative sensitivity of metabolic sensing neurons to various peripheral inputs is genetically reduced. This may provide one mechanism underlying their propensity to become obese when exposed to diets high in fat and caloric density. Thus, metabolic sensing neurons may provide a potential therapeutic target for the treatment of obesity.

Animals↗
PubMed2003

Anatomical and functional evidence for a stress-responsive, monoamine-accumulating area in the dorsomedial hypothalamus of adult rat brain.

The dorsomedial hypothalamus (DMH) plays an important role in relaying information to neural pathways mediating neuroendocrine, autonomic, and behavioral responses to stress. Evidence suggests that the DMH is a structurally and functionally diverse integrative structure that contributes to both facilitation and inhibition of the hypothalamo-pituitary-adrenal axis, depending on the nature of the stimulus and the specific neural circuits involved. Previous studies have determined that stress or stress-related stimuli elevate tissue concentrations of serotonin (5-hydroxytryptamine; 5-HT), 5-hydroxyindoleacetic acid (5-HIAA), dopamine, and noradrenaline selectively within the DMH. In order to determine the specific region of the rat DMH involved, we used high-performance liquid chromatography with electrochemical detection to measure tissue concentrations of 5-HT, 5-HIAA, dopamine, and noradrenaline within five different subregions of the DMH in adult female Lewis and Fischer rats immediately or 4 h following a 30-min period of restraint stress. Compared to unrestrained control rats, restrained rats had elevated concentrations of 5-HT, 5-HIAA, dopamine, and noradrenaline immediately after a 30-min period of restraint and had elevated concentrations of 5-HT 4 h following the onset of a 30-min period of restraint stress. These effects were confined to a specific region that included medial portions of the dorsal hypothalamic area and dorsal ependymal, subependymal, and neuronal components of the periventricular nucleus. Furthermore, these effects were observed in Lewis rats, but not Fischer rats, two closely related rat strains with well-documented differences in neurochemical, neuroendocrine, autonomic, and behavioral responses to stress. These data provide support for the existence of a stress-responsive, amine-accumulating area in the DMH that may play an important role in the differential stress responsiveness of Lewis and Fischer rats.

Age Factors↗
PubMed2003

Electrophysiological assessment of sensations arising from the bladder: are there objective criteria for subjective perceptions?

PURPOSE: Initial bladder filling sensation, first and strong desire to void are subjective perceptions that occur periodically during the urine storage mode of bladder function, representing sensory input from the lower urinary tract. To our knowledge methods for evaluating sensory bladder function are not available. We studied a simple electrophysiological procedure for the objective assessment of bladder sensations using sympathetic skin responses and surface pelvic floor electromyography. MATERIALS AND METHODS: Informed consent was provided by 8 healthy male subjects, who were administered 20 mg. furosemide and 1 l. fluid to drink. Palmar and plantar sympathetic skin responses, and surface pelvic floor electromyogram were continuously recorded during bladder filling, voluntary pelvic floor contraction and voiding. RESULTS: First desire to void evoked simultaneous sympathetic skin responses and pelvic floor contractions. This pattern appeared periodically with the desire to void sensation as well as with strong desire to void at maximum bladder capacity and it correlated well with the subjective sensation of the subjects. Voluntary pelvic floor contraction decreased the subjective intensity of the desire to void sensation as well as sympathetic skin response activity for the same short period. During voiding sympathetic skin responses almost complete absence of sympathetic skin responses was observed. CONCLUSIONS: Sensations arising from the bladder induce combined activation of sympathetic skin responses and pelvic floor activity. This coherence indicates synchronized activation and inactivation of the autonomic and somatic pathways necessary for appropriate urine storage and coordinated voiding. Our observations may introduce a new approach for objectively assessing subjective sensations arising from the urinary tract.

Adult↗
PubMed1998

Angiotensin II in central nervous system physiology.

In summary, the prevailing concept is that brain Ang II increases blood pressure by activating AT1 receptors, and that these have a neuromodulating effect to increase the activity of autonomic nervous system. Pathways for Ang II stimulating thirst and blood pressure, increased vasopressin release and sympathetic activation have been outlined. Brain RAS synthesis, while incompletely understood, is active in the absence of a peripheral RAS. Angiotensin elicits specific receptor mediated signals in neurons, particularly in the hypothalamus and brainstem. These actions are due to neuronal membrane ionic currents and the regulation of transcription factors. The areas to be explored further are characterization and functional roles of the other AT receptor subtypes, such as AT4, AT(1-7) and nuclear AT-R. Their interactions with other peptides and transmitters, and their signaling pathways need to be investigated. The story that began 100 years ago with renin is certainly not ended and will continue to unfold as further investigations with new techniques progress.

Angiotensin II↗
PubMed2003

Visual-vestibular conflict induced by virtual reality in humans.

Conflicting inputs from visual and vestibular afferents produce motion sickness and postural instability. However, the relationship of visual and vestibular inputs to each other remains obscure. In this study, we examined the development of subjective sickness- and balance-related symptoms and objective equilibrium ataxia induced by visual-vestibular conflict (VVC) stimulation using virtual reality. The subjective symptoms evaluated by Graybiel's and Hamilton's criteria got gradually worse during the VVC. The objective postural instability was not observed during the VVC, but it occurred immediately after the VVC. There was a time lag between the subjective symptoms and objective ataxia induced by VVC. Our study suggests that the VVC inputs are processed in different pathways causing subjective autonomic symptoms and postural instability in humans.

Adult↗
PubMed2001

Lipids and psychosocial status in aboriginal persons with and at risk for Type 2 diabetes: implications for tertiary prevention.

This study assessed psychosocial correlates of dyslipidemia, towards enabling improved tertiary prevention of macrovascular complications of diabetes mellitus (DM). We tested the hypothesis that psychosocial measures are related to high-density lipoprotein cholesterol (HDL-C) and triglyceride concentrations in a rural aboriginal population in British Columbia, Canada. Persons sampled were on-reserve registered Indians (n=198) with and at risk for Type 2 DM. Relationships between HDL-C and psychosocial variables were associated with glycemic status. For persons with diabetes and impaired glucose tolerance (n=44), quality of life and mastery were positively related (P<0.001), and depression inversely related (P<0.001), to HDL-C. An apparent lack of effect of behavior suggests the influence of emotional pathways involving autonomic-neuroendocrine axes. We recommend assessing mental health, and promoting mastery and diabetes quality of life through empowerment oriented diabetes management strategies, in negotiating culturally acceptable treatment of diabetic dyslipidemia for aboriginal people.

Adaptation, Psychological↗
PubMed1992

A truncated activin receptor inhibits mesoderm induction and formation of axial structures in Xenopus embryos.

Activins can induce mesoderm in embryonic explants and have been proposed as the natural inducer in Xenopus. A mutant activin receptor that inhibits activin signalling is used to show that activin is required for the induction of mesoderm in vivo and the patterning of the embryonic body plan. Blocking the activin signal transduction pathway also reveals autonomous induction of a neural marker and unmasks a relationship between activin and fibroblast growth factor.

Activin Receptors↗
PubMed1992

A choice between glycogen and delta-crystallin accumulation is made in glial cells and not influenced by overlying neurons.

Chick-embryo neuroretinal cells convert extensively into lens under low-glucose conditions, but this transdifferentiation process is blocked by high-glucose media. We have previously observed an inverse relationship between the levels of glycogen (a marker of normal retinoglial differentiation) and of delta-crystallin (a lens marker) in such cultures. However, most of the glycogen accumulated under high-glucose conditions is apparently localized in those glial (G) cells underlying clusters of neurons (N cells). We here show that glial-enriched cultures (largely depleted of N cells) both accumulate glycogen and fail to transdifferentiate in high-glucose media. Moreover, glycogen localization in groups of glial cells is unaffected by the absence of N cells. Thus the choice between normal and foreign differentiation pathways is made autonomously within the retinoglial-cell population and is not influenced significantly by the presence or absence of N cells.

Animals↗
PubMed1993

Circulating levels of soluble interleukin 2 receptors are elevated in the sera of humans with spinal cord injury.

A unique molecular regulatory mechanism or final common molecular pathway mediating the autonomic dysfunction and several pathobiologic sequelae of spinal cord injury (SCI) in humans has not been delineated. Although seemingly disparate in etiopathogenesis, much of the pathology caused by traumatic disruption of the spinal cord may be attributable to the pleiotropism demonstrated by a unique family of endogenous bioactive molecules, the interleukins. To begin testing this hypothesis, we examined the sera of patients with chronic SCI for elevations in interleukin 1 beta (IL-1 beta) and interleukin 2 receptor (IL-2R) and compared them to a control population of able-bodied subjects. In comparison to control subjects, a statistically significant increase in IL-2R was observed in patients with cervical spinal myelopathy. Elevated levels of IL-2R were not seen in paraplegic patients. Significant differences between the means and variances of serum IL-1 beta could not be detected among the study groups. We conclude that the sera of quadriplegic patients with chronic SCI contain elevated levels of IL-2R and suggest that the elevated levels of IL-2R may be of diagnostic, prognostic, and therapeutic importance.

Analysis of Variance↗
PubMed1999

Late-flowering genes interact with early-flowering genes to regulate flowering time in Arabidopsis thaliana.

To investigate the genetic mechanisms regulating the transition from the vegetative to reproductive growth in Arabidopsis, double mutants between three different early-flowering mutants, early flowering 1-1, 2-1, 3-1, (elf 1-1, 2-1, 3-1) and five different late-flowering mutants, gi-1, ft-1, fwa-1, ld-1, and fca-9, were constructed and phenotypes analyzed. Double mutants in all combinations displayed the late-flowering phenotypes which resembled their respective late-flowering parents in both flowering time and the number of vegetative leaves produced. The results indicate that five late-flowering mutants are epistatic to all three early-flowering mutants tested here. This epistatic relationship suggests that ELF1, ELF2, and ELF3 genes function upstream of these five late-flowering genes no matter if they are functioning in autonomous or photoperiod pathways. These three early-flowering genes may negatively modify the activity of most late-flowering genes to influence the time of the vegetative-to-reproductive transition in Arabidopsis.

Arabidopsis↗