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Results for “Sympathetic Fibers, Postganglionic”

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PubMed1994

Immunohistochemical studies on sympathetic and non-sympathetic nerve fibers and neuronal cell bodies in the pineal gland of cotton rats, Sigmodon hispidus.

Immunohistochemistry revealed the presence of tyrosine hydroxylase (TH)-, neuropeptide Y (NPY)-, calcitonin gene-related peptide (CGRP)- and substance P (SP)-immunoreactive nerve fibers and SP-immunoreactive neuronal cell bodies in the pineal gland of the cotton rat (Sigmodon hispidus). Abundant TH- and NPY-immunoreactive fibers were distributed evenly throughout the gland; less numerous CGRP- and SP-immunoreactive fibers were distributed in the superficial pineal and the stalk, but were scarce in the deep pineal. All the immunoreactive fibers were usually found around blood vessels. Since TH- and NPY-immunoreactive fibers in various pineal regions disappeared completely with superior cervical ganglionectomy, these fibers are all considered postganglionic sympathetic fibers. Intrapineal CGRP- or SP-immunoreactive fibers decreased considerably in number following superior cervical ganglionectomy, suggesting that some sympathetic fibers contain CGRP or SP. Bilateral bundles of nerve fibers under the transverse sinuses, corresponding to the nervi conarii, contained TH-, NPY-, CGRP- and SP-immunoreactive fibers, which continued into those distributed in the pineal capsule. In the nervi conarii, fibers immunoreactive for TH and NPY disappeared after superior cervical ganglionectomy, but those immunoreactive for CGRP and SP persisted. Thus, non-sympathetic, CGRP- and SP-immunoreactive fibers, together with sympathetic fibers, are presumed to enter the gland by way of the nervi conarii. Neuronal cell bodies, containing SP-like immunoreactivity and being possibly parasympathetic in nature, occurred occasionally in the superficial pineal.

Animals↗
PubMed1999

Evidence for an inflammation-induced change in the local glutamatergic regulation of postganglionic sympathetic efferents.

Sympathetic efferents are involved in the pain of inflammation. Thus the control of these fibers is a matter of considerable importance. In this regard, postganglionic sympathetic fibers in normal rats express ionotropic glutamate receptors. The present study tests the hypothesis that inflammation leads to a significant increase in numbers of sympathetic efferents that express these receptors. In normal rats, the percentage of fibers in the L4 and L5 sympathetic gray rami immunostained with antibodies against subunits of NMDA (NMDAR1), AMPA (GluR1), or kainate (GluR5,6,7) receptors are 29, 5 and 5%, respectively. Forty-eight hours following injection of complete Freund's adjuvant into one hindpaw, the percentages of fibers in the ipsilateral gray rami immunostained for NMDA, AMPA or kainate are 57, 52 and 48%, respectively. Thus, following inflammation there is a two-fold increase in axons expressing NMDA receptors and a ten-fold increase in axons expressing AMPA or kainate receptors. These data suggest that postganglionic activity may be enhanced by glutamate receptor activation during inflammation. Increased activity in postganglionic fibers could lead to an increased release of NE and other substances in postganglionic efferents such as prostaglandins which in turn could enhance nociceptor activity. This change in glutamate receptor organization offers a possible site of pharmacological intervention for the maladaptive symptoms that often arise following peripheral inflammation.

Animals↗
PubMed2000

Brainstem microstimulation activates sympathetic fibers in pudendal nerve motor branch.

A bilateral spino-bulbo-spinal circuit conveys information from/to the male urogenital tract and perineal muscles. This is the first electrophysiological report of another descending pathway, one which conveys output from the medullary reticular formation (MRF) to activate postganglionic sympathetic fibers contained within the motor branch of the pudendal nerve (PudM). In anesthetized rats, long latency (> 150 ms) discharges were elicited in the PudM following ipsilateral or contralateral microstimulation of the MRF. These firing bursts were not observed in rats after sectioning the lower lumbar sympathetic trunk. The most robust activation was observed when neurons in or near the lateral paragigantocellular reticular nucleus were microstimulated bilaterally. Urogenital dysfunction that occurs following severe spinal cord injury probably results from disrupting these and other supraspinal circuits.

Action Potentials↗
PubMed1993

[Sudomotor dysfunction in Parkinson's disease].

Sudomotor function was evaluated by using the sympathetic skin response (SSR) and the sweat response to intradermal acetylcholine (ACh) injection in 69 patients with Parkinson's diseases (PD). The incidence of SSR abnormality (34.8%) was as high as that of orthostatic hypotension (30.4%) and increased with the severity of the illness. Anticholinergic drug did not influence the incidence of SSR abnormality. Therefore, the SSR is useful in evaluating sudomotor efferent pathway in PD patients. Moreover, in all patients, sweat response to ACh showed a reduced number of excitable sweat glands and a low volume of sweat. In a patient in whom sweat response to ACh was markedly impaired, however, the density of acetylcholinesterase-positive unmyelinated fibers in biopsied sural nerve was in normal range. Therefore, this is considered to indicate functional disturbance of the postganglionic sympathetic fibers in PD patients, without morphological changes.

Aged↗
PubMedDate not supplied

The "Harlequin Sign". Case description and review of the literature.

Asymmetrical facial sweating and flushing has been named the "Harlequin Sign". This is a rare feature, as evident from only 12 cases described up to date. The "Harlequin Sign" represents a local autonomic dysfunction due to a cervical sympathetic deficit located at the pre or postganglionic level on the non-flushing side. We observed slow onset and progression of the "Harlequin Sign" in a 19-year-old man, with preexisting slight miosis on the non-flushing side. The differential diagnosis included other forms of dysautonomia and a secondary origin of this partial Horner's syndrome. Both pupils normally reacted to light, convergence, and pilocarpine eye-drop instillation, but the affected side showed supersensitivity to phenylephrine. Deep tendon reflexes were normal, thus excluding Adie's syndrome. The absence of cholinergic supersensitivity in the iris muscles indicated normal function of the ciliary ganglion and excluded the ocular parasympathetic deficit, also evident for the coexisting Horner's syndrome. The clinical features could be explained by assuming that the lesion was located at the level of postganglionic sympathetic fibers, probably due to trans-synaptic postganglionic neuronal degeneration at the level of the stellate ganglion, thus determining the onset of the hemifacial symptoms.

Adult↗
PubMed2001

Effects of nociceptin on cardiac norepinephrine and acetylcholine release evoked by ouabain.

We investigated whether the novel peptide, nociceptin, modulates neuronal transmission at autonomic nerve endings. Using a cardiac dialysis technique, the effects of locally applied nociceptin on cardiac acetylcholine (ACh) and norepinephrine (NE) release were examined in anesthetized cats. Dialysis probes were implanted in the left ventricular wall, with the concentration of dialysate NE or ACh serving as an indicator of NE or ACh output at cardiac sympathetic or parasympathetic nerve endings. Locally applied ouabain evoked increases in NE and ACh output. Nociceptin suppressed the ouabain induced ACh increment. The ouabain induced NE release was not altered by nociceptin. However, in the presence of desipramine (a NE uptake inhibitor), nociceptin suppressed the ouabain-induced NE release. Inhibition by nociceptin of ouabain-induced release of NE or ACh was blocked by pretreatment with nocistatin (a nociceptin action blocking peptide). Nociceptin-induced inhibition of ACh or NE release is attributable to pre-synaptic modulation rather than a reversal of the ouabain effect. These findings demonstrate that nociceptin inhibits cardiac autonomic neurotransmission via a presynaptic opioid receptor-like1(ORL1) receptor.

Acetylcholine↗
PubMed1986

Cardiac autonomic efferent activity during baroreflex in puppies and adult dogs.

Blood pressure and heart rate were recorded in 15 anesthetized puppies (6-10 wk, 1-6 kg) and 18 adult mongrel dogs (greater than 1 yr, 18-26 kg) before and during acute blood pressure changes achieved with nitroglycerin or phenylephrine (4 and 8 micrograms/kg iv). Overall heart rate responses to blood pressure changes in adults were significantly (P less than 0.05) greater than those in puppies. Following control baroreflex responses, two multifiber efferent preparations from the discrete thoracic cardiac nerves (sympathetic, n = 48; parasympathetic, n = 18) were simultaneously recorded and analyzed by microprocessor. Severing of the nerves significantly attenuated the heart rate responses to blood pressure changes in puppies only, suggesting less redundancy of the neural regulation of the sinus node in the puppy. The pressure-induced reflex changes in the sympathetic or parasympathetic efferent nerve activities were not significantly different between adult dogs and puppies. There were no significant differences in reflex activities in right-sided (n = 29) vs. left-sided (n = 19) sympathetic nerves in either puppies or adult dogs. Preganglionic sympathetic fibers in puppies (but not adult dogs) were more responsive to blood pressure changes than were postganglionic sympathetic fibers. Thus baroreceptor reflex control in the puppy is less developed than in the adult canine heart, and the maturational difference in neural regulation of the heart is at or beyond the efferent nerve terminals.

Aging↗
PubMed1996

Identification of uterine-related sympathetic neurons in the rat inferior mesenteric ganglion: neurotransmitter content and afferent input.

The rat uterus is innervated by sensory and autonomic nerves. Sensory and sympathetic fibers travel in the hypogastric nerves and are associated with the thoracolumbar spinal cord levels T13-L3. The inferior mesenteric ganglion (IMG) contains the somata of sympathetic postganglionic neurons and some of these may project axons to the uterus. Sensory and parasympathetic fibers travel in the pelvic nerve and are associated with the lumbosacral cord levels L6-S1 and pelvic ganglion (PG). We previously reported data concerning the neurochemical anatomy of the PG with regard to the uterine innervation; the present study was undertaken to characterize the neurochemical anatomy of the IMG with regard to it involvement in uterine innervation. A retrograde axonal tracer was used to verify projections of axons of IMG neurons to the uterus. Immunostaining of cryostat sections of the IMG revealed neurons immunoreactive for neuropeptide Y (NPY) and for tyrosine hydroxylase (TH). Immunostaining for the synaptic terminal protein synapsin I (SYN) revealed numerous fine terminals immediately surrounding the principal neurons and in the interneuronal spaces. Varicosities immunoreactive for calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), enkephalin (ENK), substance P (SP) and galanin (GAL) appear to be associated with principal neurons. Additional varicosities stained for nicotinamide adenine dinucleotide phosphate (reduced)-diaphorase (NADPH-d) and nitric oxide synthase (NOS), thus indicating sites of neuronal nitric oxide synthesis. This study revealed that the IMG contains uterine-related neurons and that some of the retrogradely labeled uterine-related neurons contain NPY, TH or both NPY/TH. In addition, uterine-related neurons received abundant afferent inputs indicated by SYN-immunoreactive (-ir) terminals and some of these varicosities labeled for GAL, CGRP, VIP, ENK, or NADPH-d/NOS.

Animals↗
PubMed1993

Study of sympathetic innervation of cranial bones by axonal transport of horseradish peroxidase in the rat: preliminary findings.

This study performed by intraneuronal tracing directly demonstrates the presence of sympathetic postganglionic fibers in the cranial vault of the rat. Superior cervical sympathetic ganglia were injected with horseradish peroxidase (HRP), and after a 48-hour period, to permit anterograde axonal transport, the animals were sacrificed after in situ perfusion. An area of the calvaria that included portions of the frontal and parietal bones was fixed, decalcified and sectioned. HRP-containing axons were localized in the developing frontal and parietal bones of the calvaria. Adrenergic innervation was not demonstrated in sutural tissue (superior sagittal, coronal or metopic) by this technique. To our knowledge, this study is the first to trace sympathetic nerve fibers in the rat calvaria by intra-axonal transport of HRP.

Animals↗
PubMed2004

Involvement of central and peripheral histamine H(3) receptors in the control of the vascular tone and oxygen uptake in the mesenteric circulation of the rat.

Data concerning cardiovascular effects of peripherally and centrally located histamine H(3) receptor stimulation are contradictory, and despite excessive studies their role in the control of the cardiovascular function have not been cleared yet. Effect of histamine H(3) receptors activation have been attributed to modulation of sympathetic system activity but exact role of peripherally and centrally located histamine H(3) receptors stimulation in the modulation of vascular tone of the mesentery and intestinal metabolism remains unexplored. Aim of the present study was to evaluate the role of centrally and peripherally located histamine H(3) receptors in the modulation of vascular tone of the mesentery and metabolic activity of intestinal tissue. In anesthetized rats total mesenteric blood flow (MBF), mucosal intestinal blood flow (LDBF), intestinal oxygen uptake (VO(2)) and arterial pressure (AP) were determined. Intestinal arterial conductance (C) was also calculated. Administration of the selective histamine H(3) receptor agonist imetit (10 micromol/kg i.a) evoked marked changes in hemodynamic and metabolic parameters; MBF, LDBF, C and VO(2) were significantly increased, whereas AP was significantly decreased. Pretreatment with histamine H(3) receptor antagonist clobenpropit (4 micromol/kg i.a.) abolished imetit-induced circulatory and oxygen uptake responses. Clobenpropit (4 micromol/kg i.a.) alone failed to affect the MBF, LDBF, AP, C and VO(2) values. Central administration of imetit (0.1 micromol i.c.v.) markedly increased AP and decreased MBF, LDBF, C and VO(2). Pretreatment with histamine H(3) receptor antagonist clobenpropit (0,4 micromol i.c.v.) diminished circulatory and metabolic responses to centrally injected imetit. Central histamine H(3) receptors blockade by clobenpropit evoked no significant changes in the mesenteric arterial and mucosal microcirculatory blood flow, intestinal metabolism and mean arterial pressure. We conclude that, peripheral histamine H(3) receptors when stimulated decreases vasoconstrictory tone of the mesenteric artery and precapillary structures and evokes increase of intestinal oxygen uptake. This might be in part due to inhibition of sympathetic postganglionic fibers vasopressor activity. Central histamine H(3) receptor stimulation activates vasoconstrictory sympathetic adrenergic system with possible involvement of other, presumably non-histaminergic receptors system. At basal conditions neither central nor peripheral histamine H(3) receptors are involved in the control of mesenteric macro- and microcirculation and intestinal oxygen consumption.

Animals↗
PubMed1978

Categories of axons in the inferior cardiac nerve of the cat.

Myelinated and unmyelinated axons in the inferior cardiac nerve of the cat were examined to determine how many axons were (1) sensory, (2) preganglionic sympathetic, and (3) postganglionic sympathetic. In one group of cats, a segment was removed from the middle of the inferior cardiac nerve as a control, and the proximal and distal stumps of the nerve were examined one week later. In another group of cats, the control segment of nerve was removed and the first thoracic white ramus communicans and sympathetic trunk were cut proximal to the stellate ganglion, followed in one week by examination of the proximal and distal stumps of the inferior cardiac nerve. In still another group of cats, the first five thoracic spinal nerves were cut just distal to the dorsal root ganglion. The counts of myelinated and unmyelinated axons after these surgical procedures indicated that, in the cat inferior cardiac nerve, all or almost all of the approximately 30,000 unmyelinated axons and 10 percent of the myelinated axons are postganglionic sympathetic fibers, and that approximately 90 percent of the myelinated axons are sensory.

Animals↗
PubMed1978

Electron-microscopic analysis of the mouse facial nerve near the geniculate ganglion.

An electron-microscopic analysis of the mouse facial nerve near the geniculate ganglion shows that there are, on the everage, 603 more nerve fibers in the portion of the nerve distal to the geniculate ganglion than there are in the part proximal to the ganglion. The average distal increase in the number of unmyelinated fibers is 444 and that in the myelinated fibers is 165. The somatic motor nerve fibers and the parasympathetic fibers in the mouse facial nerve may not contribute to the distal excess. It is possible that the increase in the number of unmyelinated fibers distal to the geniculate ganglion is mainly due to the presence of postganglionic sympathetic fibers in the facial trunk distal to the geniculate ganglion and the greater petrosal nerve. The distal increase in the number of myelinated fibers may be mainly contributed by the sensory fibers.

Animals↗
PubMed1993

Further substantiation of a significant role for the sympathetic nervous system in inflammation.

This study provides significant new evidence substantiating a role of the postganglionic sympathetic neuron in plasma extravasation in the knee-joint of the rat. Increased plasma extravasation produced by the potent inflammatory mediator bradykinin was mimicked by 6-hydroxydopamine, a selective stimulator of sympathetic fibers. Various treatments (chemical sympathectomy, co-perfusion with the local anesthetic lidocaine, or co-perfusion with depolarizing concentrations of potassium) similarly modulated plasma extravasation induced by both bradykinin and 6-hydroxydopamine, but not that produced by platelet activating factor. We also showed that bradykinin is able to release norepinephrine in the knee-joint, indicating action on the sympathetic postganglionic neuron. In summary, these experiments provide substantial additional evidence supporting a significant contribution of the sympathetic post-ganglionic neuron terminal to inflammatory plasma extravasation.

Animals↗
PubMed1982

An analysis of the axon populations in the nerves to the pelvic viscera in the rat.

The present study uses selective surgical ablations combined with electron microscopic analyses to determine the number of axons in various categories in rat hypogastric, pelvic, and pudendal nerves, these being the nerves to the pelvic viscera in this animal. Unmyelinated fibers predominate in all of these nerves. One of the most significant findings is that the pelvic nerve contains almost as many postganglionic sympathetic fibers as the hypogastric nerve. Previous investigators thought that the pelvic nerve supplied the parasympathetic inflow and the hypogastric nerve the sympathetic inflow to the pelvic viscera. The finding that there is a sizable sympathetic component in the pelvic nerve negates this idea, at least for the rat, and presumably calls for a reevaluation of the syndromes that arise from pelvic as opposed to hypogastric nerve section. Other findings of interest are (1) that there are unmyelinated efferent axons in the pudendal nerve, indicating that the pudendal is not a typical somatic nerve, (2) that the hypogastric nerve has a very small sensory component, and (3) that there are fibers surviving in the distal stumps of all these nerves, particularly the pelvic and hypogastric nerves.

Adrenergic Fibers↗
PubMed1993

Sympathetic innervation of the young canine heart using antero- and retrograde axonal tracer methods.

The present study was performed to determine the origin of cardiac sympathetic postganglionic fibers and to demonstrate their distribution in the heart. Young dogs were used in this study. Wheat germ agglutinin-horseradish peroxidase (WGA-HRP) was injected into various regions of the heart, and cholera toxin B subunit (CTB) and WGA-HRP were injected into the middle cervical ganglion or the stellate ganglion. In our retrograde axonal transport study, a large number of WGA-HRP-labeled cells were observed in the middle cervical and stellate ganglia bilaterally. Only a small number of the labeled cells were observed in the superior cervical ganglia bilaterally. In the anterograde axonal transport study, CTB and WGA-HRP labels showed terminal-like structures in the intrinsic ganglia located in the sinoatrial node, left atrium, and the origin of the ascending aorta. The labeled fibers were also observed around the coronary arteries.

Animals↗