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At least 811 records · Page 45Linked to original sources
PubMed2002

Effects of the head-down tilt posture on postnatal development of the aortic baroreflex in the rabbit.

To clarify the effects of the head-down tilt (HDT) posture on the postnatal development of the aortic baroreflex, we raised rabbits from 3-4 weeks of age for 34-36 d in this posture, which simulates the headward shift of body fluid in space, and examined the structural and functional characteristics of the aortic nerves and baroreflex responses. The rabbits were divided into 3 different groups: 20 degrees HDT, environmental control (EC), and vivarium control (VIV). Left aortic nerve activity (ANA) at basal arterial pressure was defined as 100%, and the maximum ANA at maximal increase in arterial pressure was 265+/-103% (mean+/-SD, n=5) in the HDT, 482+/-170% (n=4) in the EC, and 677+/-491% (n=4) in the VIV groups. The minimum ANA at maximal decrease in arterial pressure was 67.3+/-13.8% in the HDT, 40.1+/-10.2% in the EC, and 38.6+/-13.8% in the VIV groups. The maximal change of ANA in response to maximal change in arterial pressure in the HDT group was significantly less than that of either the EC or VIV group (p<0.05). The average baroreflex gain in the HDT group was significantly less than in the VIV group (p<0.05). The number of unmyelinated fibers in the left aortic nerve in the HDT group was significantly less than that of each control group (p<0.05). Thus the development of the aortic baroreflex system is apparently depressed by the HDT posture, suggesting that similar consequences will be observed in mammals that develop in space.

Adrenal Glands↗
PubMed2003

Electro-acupuncture stimulation effects on duodenal motility in anesthetized rats.

The effect of electro-acupuncture stimulation (EAS) on duodenal motility was examined in anesthetized, artificially ventilated rats. EAS was applied to the abdominal area or to a hindpaw for 30 s at stimulus intensities of 0.1-10.0 mA with a stimulus frequency of 20 Hz. The duodenal motility was measured using the balloon method at a position about 1.5 cm caudal from the pylorus. Duodenal motility was inhibited by EAS at intensities of more than 5.0 mA (suprathreshold of group IV afferent excitation) when applied to the abdominal area. The duodenal inhibitory response existed after bilateral vagotomy or spinal transection, but was abolished by sectioning bilateral splanchnic nerves. Duodenal motility was facilitated by EAS at intensities of more than 2.0 mA (subthreshold of group IV, and suprathreshold for groups II+III afferent excitation) when applied to a hindpaw. The duodenal facilitatory response by EAS to a hindpaw existed after sectioning the splanchnic nerves, but disappeared after bilateral vagotomy or spinal transection. Furthermore, repetitive electrical stimulation of vagal efferent nerves enhanced duodenal motility, while repetitive electrical stimulation of the splanchnic efferent nerves inhibited the motility. It was concluded that the inhibitory response of duodenal motility elicited by EAS to the abdominal area is a spinal reflex response involving splanchnic inhibitory efferent nerves, and the enhanced response of duodenal motility by EAS to a hindpaw is a supraspinal reflex response involving vagal excitatory nerves.

Abdomen↗
PubMed2006

Central nervous system circuitry and peripheral neural sympathetic activity responsible for essential hypertension.

Both clinical and experimental studies dealing with patients affected by idiopathic or essential hypertension (EH) are devoted to the great deal of physiological, pharmacological and pathological as well as therapeutical issues of EH. However, most articles devoted to EH do not refer to the central nervous system mechanisms underlying this disease and the channels which allow that these mechanisms are funneled to the peripheral autonomic nervous system and trigger this cardiovascular disorder. In the present review article we attempted to reach this target devoted to the central nervous system circuitry involved in the cardiovascular pathophysiology. We postulated that EH depends on the predominance of the binomial A5 noradrenergic (NA) nucleus + median raphe serotonergic (5-HT) nucleus over the (A6)-NA + dorsal raphe-5HT nuclei. This hypothesis receives additional support from our results obtained throughout the neuropharmacological therapy of this type of neurophysiological disorder. Our therapeutical strategy is addressed to enhance the activity of the (A6)-NA + dorsal raphe-5HT binomial circuitry.

Acetylcholine↗
PubMed2002

Sphincter and nerve preserving total mesorectal excision.

The summer of 2002 has seen the introduction of two new key words in the literature on rectal carcinoma. The words are TME Workshop. Papers attesting to a major impact on rectal cancer outcomes in Norway, Sweden, and Holland, are the background to two major papers in the August British Journal of Surgery, one from Ireland and one from Sweden plus a leading article from a professor in Singapore entitled "Adjuvant therapy for rectal cancer cannot be based on the results of other surgeons".

Autonomic Pathways↗
PubMed2003

The effectiveness of treatments of diabetic autonomic neuropathy is not the same in autonomic nerves supplying different organs.

The aim of the study was to investigate antioxidant (alpha-lipoic acid [LA]) and gamma-linolenic acid treatments in the prevention of changes in autonomic nerves induced in streptozotocin-diabetic rats. Autonomic nerves supplying the heart, penis, and gut were examined using immunohistochemical and biochemical techniques. LA and gamma-linolenic acid (present in evening primrose oil [EPO]) were administered as dietary supplements ( approximately 80 and 200 mg. kg(-1). day(-1), respectively). LA treatment prevented the diabetes-induced decrease of norepinephrine (NA) in the heart and of type I nitric oxide synthase (NOS-I) expression in erectile tissue of the penis but failed to prevent diabetes-induced changes in NA-, vasoactive intestinal polypeptide-, or calcitonin gene-related peptide-containing nerves supplying the ileum. LA partially prevented and EPO totally prevented the increase in NOS-I activity induced by diabetes in the ileum. EPO treatment failed to prevent any other diabetes-induced changes in the heart, penis, or ileum. These results demonstrate that, whereas LA treatment is more effective than EPO in preventing diabetes-induced changes in autonomic nerves, the effectiveness of LA treatment varies with the target organ studied. Diabetes-induced changes in nerves supplying the ileum are more resistant to treatment than those of the heart and penis.

Animals↗
PubMed2006

Effect of electroacupuncture at Sibai on the gastric myoelectric activities of denervated rats.

AIM: To explore the mechanism of the exciting effects of electro-acupuncture (EA) at Sibai on the gastric myoelectric activities. METHODS: A total of 32 rats were randomly divided into four groups. Through intraperitoneal injection with atropine (the anti-cholinergic agent by blockade of muscarinic receptors), hexamethonium (automatic nerve ganglion-blocking agent) and reserpine (anti-adrenergic agent by depleting the adrenergic nerve terminal of its norepinephrine store), effects of EA at Sibai on the gastric myoelectric activities of the denervated rats were observed. RESULTS: After intraperitoneal injection of atropine and hexamethonium, the average amplitude and ratio of period to time in the phase of high activity of gastric myoelectric slow wave, and the average numbers of the peaks of gastric myoelectric fast wave were significantly decreased (P<0.01, P<0.05, P<0.01), while after intraperitoneal injection of reserpine, the aforementioned three parameters were increased (P<0.01, P<0.05, P<0.01). EA at Sibai point partially relieved the inhibitory effect of atropine and hexamethonium on the gastric myoelectric activities in the rats (P<0.05 or P>0.05). CONCLUSION: Cholinergic and adrenergic nervous systems and autonomic nerve ganglion participate in the peripheral passage of the controlling effects of EA at Foot Yangming Channel on gastrointestinal tract.

Acupuncture Points↗
PubMed2007

Environmental noise alters gastric myoelectrical activity: Effect of age.

AIM: To evaluate the effect of age and acoustic stress on gastric myoelectrical activity (GMA) and autonomic nervous system function. METHODS: Twenty-one male subjects (age range 22-71 years, mean 44 years) were recruited and exposed, in random order, to three auditory stimuli (Hospital noise, conversation babble and traffic noise) after a 20-min baseline. All periods lasted 20 min and were interspersed with a 10 min of recovery. GMA was obtained using a Synectics Microdigitrapper. Autonomic nerve function was assessed by monitoring blood pressure and heart rate using an automatic recording device. RESULTS: Dominant power tended to decrease with increase of age (P < 0.05). The overall percentage of three cycle per minute (CPM) activity decreased during exposure to hospital noise (12.0%, P <0.05), traffic noise (13.9%, P < 0.05), and conversation babble (7.1%). The subjects in the younger group (< 50 years) showed a consistent reduction in the percentage of 3 CPM activity during hospital noise (22.9%, P < 0.05), traffic noise (19.0%, P < 0.05), and conversation babble (15.5%). These observations were accompanied by a significant increase in bradygastria: hospital noise (P < 0.05) and traffic noise (P < 0.05). In contrast, the subjects over 50 years of age did not exhibit a significant decrease in 3 CPM activity. Regardless of age, noise did not alter blood pressure or heart rate. CONCLUSION: GMA changes with age. Loud noise can alter GMA, especially in younger individuals. Our data indicate that even short-term exposure to noise may alter the contractility of the stomach.

Adult↗
PubMed2003

Alloreactive CD4 T cell activation in vivo: an autonomous function of the indirect pathway of alloantigen presentation.

Activation of alloreactive CD4 T cells occurs via the direct and indirect pathways of alloantigen presentation. A novel TCR/alloantigen transgenic system was designed that permitted in vivo visualization of CD4 T cell priming through these pathways. When both pathways of alloantigen presentation were intact, CD4 T cell activation in response to cardiac allografts was rapid and systemic by day 4 after transplantation, in contrast to that seen in response to skin allografts, which was delayed until 10-12 days after transplantation. Despite this systemic CD4 T cell activation in response to cardiac allografts, there was a paucity of activated graft-infiltrating CD4 T cells at 4 days posttransplantation. This finding suggests that the initial priming of alloimmune CD4 T cell responses occurs within draining lymphoid organs. Furthermore, alloantigens derived from cardiac allografts failed to promote thymic negative selection of developing thymocytes expressing the alloreactive TCR clonotype. In the absence of a functional direct pathway, the kinetics of activation, anatomic localization, and effector function of alloreactive CD4 T cells remained unchanged. Overall, the present study defines the anatomic and temporal characteristics of CD4 T cell alloimmune responses and demonstrates that CD4 T cell priming via the indirect pathway proceeds optimally in the absence of the direct pathway of alloantigen presentation.

Adoptive Transfer↗
PubMedDate not supplied

An investigation of an autonomic innervation of the vertebral artery using monoamine histofluorescence.

Blood flow to the hindbrain, via the paired vertebral arteries, must be uncompromised for adequate neurological functioning of its vital centres. Therefore, it would seem unlikely that the intracranial vertebral artery would need to vasoconstrict, thus reducing its blood flow. In order to investigate the existence and location of a noradrenaline-mediated constrictor mechanism in the wall of the intracranial vertebral artery, transverse sections of ten baboon and ten monkey vessels were stained with sucrose-potassium phosphate-glyoxylic acid (counterstained with malachite-green). This method allows the visualisation of catecholaminergic nerves when the sections are exposed to ultraviolet light. In this study of primate vascular tissue, however, none of the monkey or baboon vertebral artery sections showed the presence of noradrenergic nerves in the tunica media - tunica adventitia junction or penetrating the tunica media of the arteries. These findings indicate that the intracranial vertebral artery does not have a neurogenic vasomotor function in primates.

Adrenal Medulla↗
PubMed1999

Current issues in colorectal cancer surgery.

Increased understanding of the pathology and natural history of colorectal cancer has led to significant advances in the management of this disease. Surgical management of rectal cancer currently includes a spectrum of operative procedures ranging from radical operations to innovative sphincter-preserving techniques. At one end of the spectrum, 5% to 10% of patients present with small, superficially invasive rectal cancers amenable to a curative local excision. At the other end, a subset of patients present with locally advanced rectal cancers that require multimodality therapy, including sharp pelvic dissection with en-bloc resection of involved organs. However, the majority of rectal cancer patients present with nonfixed, yet deeply invasive, lesions requiring either a low anterior resection (LAR) or an abdominal perineal resection (APR). This report will address the controversies in the surgical management of colorectal cancer.

Anastomosis, Surgical↗
PubMed1999

[Surgical anatomy of pelvic nerves].

A good knowledge of the anatomy of the mesorectum and pelvic autonomic nerves allows the colorectal surgeon to reconcile both oncologic and functional results in rectal cancer excision. The author describes the anatomy of the systemic and autonomic pelvic nerves and describes techniques designed to avoid nerve damage during rectal cancer excision.

Adult↗
PubMed2000

[Late manifestation of radiation injury to the plexus brachialis and plexus lumbosacralis].

Radiotherapy of breast cancer, cervical cancer, testicular tumours and lymphoma is one of the most effective therapy options. Damage to the nervous system, in particular the brachial and lumbar plexus, is rare and typically leads to development of progressive sensory disturbances and motor weakness after years-long latency. We present two cases exemplifying the diagnostic problems in differentiating between radiation-induced injury and recurrence of the primary tumour. A clinical course with sensorimotor symptoms and signs progressing over months, electomyographic recording of myokymic discharges, and absence of a space-occupying mass suggest late-onset radiation-induced plexopathy. The literature on pathogenesis and incidence of radiation-induced plexopathy is reviewed.

Aged↗
PubMed2000

Cardiac Denervation and Cardiac Function.

With respect to neural control of the heart, intrathoracic ganglia and their interconnections form the final common pathway for autonomic modulation of regional cardiac function. In this review, data are presented indicating that such ganglia that include those distributed on the heart contain afferent (sensory) and efferent (motor) neurons that intercommunicate via local circuit neurons. The intrathoracic reflexes involving these neurons function in a coordinated fashion with central neurons located in the spinal cord, brain stem, and supraspinal central neuronal regions to regulate cardiac output on a beat-to-beat basis. The focus of this review is the putative role that these various populations of intrathoracic neurons play in regulating normal cardiac function and, in particular, how their interactions can become altered following their decentralization or in the presence of altered regional cardiac function. It is proposed that a thorough understanding of the interactions that occur among the hierarchy of neurons within intrinsic cardiac and intrathoracic extracardiac ganglia is required in order to assess cardiac regulation in normal as well as diseased states.

Journal Article↗
PubMed2000

Inhibition of the carotid baroreflex by urinary bladder distension.

OBJECTIVE: The cardiovascular responses to urinary bladder distension include a rise in arterial blood pressure, an increase in vascular resistance and heart rate, which are abolished by sectioning the pelvic and hypogastric nerves. There are indications in the literature that inputs from the arterial baroreceptors and urinary bladder converge at the same autonomic efferent pathways. Recent data provided evidence of a partial inhibitory action of the carotid baroreflex on the reflex cardiovascular responses evoked by bladder distension. In this study, we investigate the influence of urinary bladder distention upon cardiovascular responses elicited by carotid baroreceptor stimulation. METHODS: Wistar Rats were anaesthetised with alpha-choloralose (80 mg/kg, i.p.) supplemented as necessary. The carotid sinus was stimulated randomly with different volumes of saline (0.5-2.0 ml). The ureters were ligated and the bladder was cannulated. Arterial blood pressure (BP), ECG, heart rate (HR), and bladder pressure (BLP) were monitored. Baroreceptor stimulation was undertaken on two levels of BLP (2 and 20 cmH2O). The cardiovascular response to baroreceptor activation was assessed as the maximal variation of BP, HR and R-R interval for different volumes of saline injected. RESULTS: Our results showed that in all tests baroreceptor stimulation evoked a decrease in BP and HR but the magnitude of these responses was significantly different for each volume of saline and for two levels of BLP. The effectiveness and reproducibility of responses to these stimuli were confirmed by injecting a fixed volume of saline into the carotid sinus of two animals at two levels of BLP. In five animals, the variation in BP increased as the magnitude of the stimulus to the baroreceptor increased. However, the response was reduced with increased BLP. The fitted regression line was calculated for all the tests (n = 82; s = 8.2; Yint = 0.62 for BLP = 2 cmH2O; s = 9.5; Yint = 2.9; r = 0.69 for BLP = 20 cmH2O). Similar effects were observed and similar patterns of regression lines were obtained with regard to HR changes (n = 48; s = 13.3; Yint = 2.7; r = 0.82 for BLP = 2 cmH2O; s = 15.8; Yint = 0.89; r = 0.76 for BLP = 20 cmH2O) and interval changes (n = 48; s = 7.1; Yint = 4.3; r = 0.78 for BLP = 2 cmH2O; s = 8.5; Yint = 0.2; r = 0.76 for BLP = 20 cm H2O). CONCLUSIONS: These data suggest that the cardiovascular responses evoked by carotid baroreceptor stimulation are significantly different when the urinary bladder is empty or full with the response diminishing as the urinary bladder is distended.

Animals↗
PubMed1995

The peptidergic innervation of human coronary and cerebral vessels.

It is now well established that in addition to nerves containing classical transmitters, the mammalian vascular system is also supplied by nerve fibre subpopulations containing several vasoactive peptides. The precise function of these peptides (neuropeptide Y, calcitonin gene-related peptide, vasoactive intestinal polypeptide, somatostatin and the tachykinins) is still unknown, however, their widespread occurrence in perivascular nerves indicates that they are likely candidates for a role in the neurogenic regulation of the vascular system. It has been suggested that they may exert a direct vasomotor action via their own receptors and/or modulate the release and action of other vascular transmitters. Recently, several studies have focused on the supply of nerve fibres storing neuropeptides in the coronary and cerebral vasculature of laboratory animals, however, little is known on the distribution of these putative transmitters in human coronary and cerebral vessels. In this paper, the immunocytochemical evidence that several neuropeptides are localized in subpopulations of afferent and efferent nerve fibres supplying the human coronary and cerebral vasculature is focused.

Autonomic Pathways↗