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PubMed2001

Magnetization transfer and diffusion tensor MR imaging of basal ganglia from patients with multiple sclerosis.

Although post-mortem studies have shown that lesions of multiple sclerosis (MS) can be detected in the basal ganglia, conventional T2-weighted magnetic resonance (MR) imaging is poorly sensitive for detecting such abnormalities. This study was performed to investigate whether magnetization transfer (MT) and diffusion tensor MR imaging are able to detect in vivo basal ganglia changes in patients with MS. After image coregistration, MT ratio (MTR) and mean diffusivity (&Dmacr;) maps were obtained and MTR and &Dmacr; values of the putamen, head of the caudatus and thalamus measured from 31 patients with clinically definite MS and 14 age- and sex-matched healthy volunteers using region of interest analysis. Although we found slightly decreased MTR and increased &Dmacr; in the basal ganglia from patients compared to controls, suggesting increased extra-cellular water and reduced amount of 'barriers' restricting water molecular motion in the basal ganglia of patients with MS, none of the differences was statistically significant. These data suggest that the more sophisticated MR probes of tissue disruption and cellular integrity are no more sensitive than current conventional imaging for detecting basal ganglia abnormalities in patients with MS.

Adult↗
PubMed2002

Diabetic cystopathy correlates with a long-term decrease in nerve growth factor levels in the bladder and lumbosacral dorsal root Ganglia.

PURPOSE It has been proposed that a deficiency in the axonal transport of nerve growth factor (NGF) may have an important role in inducing diabetic neuropathy, which contributes to diabetic cystopathy. Therefore, in streptozotocin (Sigma Chemical Co., St. Louis, Missouri) induced diabetic rats we investigated the relationship of bladder function with NGF levels in the bladder and lumbosacral dorsal root ganglia, which contain afferent neurons innervating the bladder. MATERIALS AND METHODS At 6 and 12 weeks after the induction of diabetes with streptozotocin (65 mg./kg. intraperitoneally) the effects of diabetes on Adelta afferent fiber dependent, conscious voiding were evaluated by metabolic cage measurements and awake cystometry. The effects of diabetes on C-fiber mediated bladder nociceptive responses were also investigated by cystometry with intravesical instillation of 0.25% acetic acid in the rats under urethane anesthesia. NGF levels in the bladder and L6 to S1 dorsal root ganglia were measured by enzyme-linked immunosorbent assay 3, 6, 9 and 12 weeks after streptozotocin injection. RESULTS In diabetic rats NGF levels in the bladder and L6 to S1 dorsal root ganglia were significantly decreased 12 weeks after streptozotocin injection (p <0.01). In cystometry and metabolic cage studies bladder capacity and post-void residual volume were significantly increased 12 weeks after streptozotocin injection (p <0.01). Bladder nociceptive responses revealed by a reduction in inter-contraction intervals after acetic acid infusion were significantly decreased in a time dependent manner 12 weeks after streptozotocin injection.CONCLUSIONS Rats with streptozotocin induced diabetes mellitus showed a significant time dependent decrease in NGF levels in the bladder and L6 to S1 dorsal root ganglia that was associated with voiding dysfunction attributable to defects in Adelta and C-fiber bladder afferents. Therefore, reduced production of NGF in the bladder and/or impaired transport of NGF to L6 to S1 dorsal root ganglia, which contain bladder afferent neurons, may be an important mechanism inducing diabetic cystopathy.

Animals↗
PubMed1999

Motor actions of cannabinoids in the basal ganglia output nuclei.

The levels of CB1 cannabinoid receptors in the basal ganglia are the highest in the brain, comparable to the levels of dopamine receptors, a major transmitter in the basal ganglia. This localization of receptors is consistent with the profound effects on motor function exerted by cannabinoids. The output nuclei of the basal ganglia, the globus pallidus (GP) and substantia nigra reticulata (SNr), apparently lack intrinsic cannabinoid receptors. Rather, the receptors are located on afferent terminals, the striatum being the major source. Cannabinoids blocked the inhibitory action of the striatal input in the SNr. Furthermore, cannabinoids blocked the excitatory effect of stimulation of the subthalamic input to the SNr revealing, along with data from in situ hybridization studies, that this input is another likely source of cannabinoid receptors to the SNr. Similar actions of cannabinoids were observed in the GP. Behavioral studies further revealed that the action of cannabinoids differs depending upon which input to the output nuclei of the basal ganglia is active. The inhibitory striatal input is quiescent and the cannabinoid action is observable only upon stimulation of the striatum, while the noticeable effect of cannabinoids under basal conditions would be on the tonically active subthalamic input. These data suggest that the recently discovered endogenous cannabinergic system exerts a major modulatory action in the basal ganglia by its ability to block both the major excitatory and inhibitory inputs to the SNr and GP.

Animals↗
PubMed2004

Role of basal ganglia-brainstem systems in the control of postural muscle tone and locomotion.

This chapter argues that a basal ganglia-brainstem system throughout the mesopontine tegmentum contributes to an automatic control of movement that operates in conjunction with voluntary control processes. Activity of a muscle tone inhibitory system and the locomotion executing system can be steadily balanced by a net excitatory cortical input and a net inhibitory basal ganglia input to these systems. We further propose that dysfunction of the basal ganglia-brainstem system, together with that of the cortico-basal ganglia loop, underlies the pathogenesis of motor disturbances expressed in basal ganglia diseases.

Animals↗
PubMed1993

Culture of isolated embryonic chick dorsal root ganglia at an air-liquid interface: a simple method for studying the mechanism and control of neurite outgrowth.

Extensive neurite outgrowth occurs within 24 h from explants of embryonic chick dorsal root ganglia floated on the surface of serum-free culture medium. The amount of neurite outgrowth was less in culture medium containing serum albumen and varied systematically with the concentration of nerve growth factor (NGF). Compared with outgrowth from floating ganglia, the NGF-dependent outgrowth of neurites from ganglia stuck to coated substrata was much less on polylysine, but outgrowth was more extensive on a laminin-coated substrate. Neurites growing out from floating ganglia showed more fasciculation than those growing out from adherent ganglia. This new, simple preparation provides a serum- and substrate-independent system for studying mechanisms of neurite outgrowth and for quantitative bioassay for potential neurotrophic factors or for factors which influence neurite fasciculation.

Animals↗
PubMed1997

Identification of the cholinergic neurons in guinea-pig sphincter of Oddi ganglia.

The muscular tone of the sphincter of Oddi (SO) can be up- or down-regulated by neurons that lie within ganglia in the wall of the tissue. Previous studies have demonstrated that neurons in the ganglia of the guinea-pig SO can be classified into two major populations, one of which expresses tachykinins and enkephalin and another which expresses nitric oxide synthase. Although results of previous pharmacological studies indicate that acetylcholine is released in the SO, the neurons that express this neurotransmitter have not previously been identified. This study was conducted to establish which neurons in the ganglia of the guinea-pig SO are cholinergic by examining the distribution of choline acetyltransferase (ChAT) immunoreactivity, since the enzyme, ChAT is necessary for acetylcholine synthesis. Choline acetyltransferase immunoreactivity was intense and widespread in the ganglionated plexus of the SO. ChAT-immunoreactive nerve fibers were present in ganglia, interganglionic fiber bundles and in the circular muscle layer. Neurons that were immunoreactive for ChAT comprised about 69% of the population and most of these neurons were also tachykinin-immunoreactive. Co-expression of ChAT and nitric oxide synthase was not observed in nerve cell bodies or nerve fibers. Data from this study support the concept that SO ganglia are largely made up of two populations of neurons, one excitatory and the other inhibitory, on the basis of their chemical coding. The excitatory neurons are cholinergic and co-express tachykinin and opiate peptides and the inhibitory neurons are ChAT-negative and express nitric oxide synthase.

Animals↗
PubMed1997

Involvement of the pelvic plexus and the suprarenal ganglia in the neuropeptide Y (NPY) innervation of the cervix and the uterus of the rat.

The involvement of the pelvic plexus and suprarenal ganglia in the neuropeptide Y (NPY) innervation of the genital tract was studied in the female rat by means of denervation experiments and retrograde tracing studies. Removal of the paracervical ganglia caused a significant decrease of the NPY-immunoreactive nerve density and NPY concentration in the lower part of the genital tract: cervix, uterine body and lower part of the uterine horn. The decrease in NPY concentration in these three regions was more pronounced after lesion of the pelvic plexus. Lesion of the ovarian nerve plexus caused a depletion in the NPY-immunoreactive nerve fibres and a decrease in NPY concentration in the upper part of the uterine horn. Pelvic nerve section, inferior mesenteric ganglia excision and superior ovarian nerve section had no effect on the NPY innervation in the genital tract. Injection of fluorogold into the cervix and lower part of the uterus combined with immunohistochemistry revealed that 87.5% of labelled neurons in the pelvic plexus were NPY-immunoreactive. Following injection of fluorogold into the upper part of the uterus, 92% of labelled neurons in the suprarenal ganglia were NPY-immunoreactive. Treatment with 6-hydroxydopamine revealed that the NPY-immunoreactive nerve fibres were non-noradrenergic in the cervix, but were noradrenergic in the upper part of the uterus. In the uterine body and lower part of the uterine horn, both noradrenergic and non-noradrenergic NPY-immunoreactive nerve fibres were observed. These data demonstrate the major contribution of pelvic plexus neurons in the non-noradrenergic NPY innervation of the lower part of the genital tract, and the involvement of the suprarenal ganglia in the noradrenergic NPY innervation of the upper part of the uterus via the ovarian nerve plexus.

Animals↗
PubMed1998

Vagal efferent and afferent innervation of the rat esophagus as demonstrated by anterograde DiI and DiA tracing: focus on myenteric ganglia.

Anterograde tracing with the carbocyanine tracer DiI and the aminostyrol derivative DiA was used to selectively label fibers from the nucleus ambiguus, dorsal motor nucleus and nodose ganglion, respectively, terminating in the rat esophagus, and to compare them with the innervation of the gastric fundus in the same animals. Ambiguus neurons terminated on motor endplates distributed mainly to the ipsilateral half of the esophagus. There was no evidence of preganglionic innervation of myenteric ganglia from ambiguus neurons. Neurons of the dorsal motor nucleus supplied sparse fibers to only about 10% of enteric ganglia in the esophagus while they innervated up to 100% of myenteric ganglia in the stomach. Neurons of the nodose ganglion terminated profusely on more than 90% of myenteric ganglia of the esophagus and on about 50% of ganglia in the stomach. Afferent vagal fibers were also frequently found in smooth muscle layers starting at the esophago-gastric junction. In contrast, they were extremely rare in the striated muscle part of the esophagus. These morphological data suggest a minor influence of neurons of the dorsal motor nucleus and a prominent influence of vagal afferent terminals onto myenteric neurons in the rat esophagus.

Animals↗
PubMed1998

Diurnal rhythms in norepinephrine and acetylcholine synthesis of sympathetic ganglia, heart and adrenals of aging rats: effect of melatonin.

The effect of aging and melatonin on 24-h rhythms in tyrosine hydroxylase activity and 3H - choline conversion into 3H - acetylcholine were examined in cervical, stellate, coeliac-mesenteric and hypogastric ganglia, and in the adrenal medulla and heart of rats. Young (50 days old) and old (18 months old) rats received evening injections of 10 or 100 microg of melatonin or its vehicle for 17 days. In superior cervical, stellate and coeliac-superior mesenteric ganglia, as well as in the adrenal medulla, norepinephrine and acetylcholine synthesis attained maximal values at night (c.a. 2030-0100 h). In the hypogastric ganglion, maximal tyrosine hydroxylase activity occurred at night at both studied ages. Two maxima in acetylcholine synthesis were detected in hypogastric ganglion of young rats (c.a. 1300 h and 0100 h, respectively) while in old rats a single maximum was observed at noon. Cardiac tyrosine hydroxylase activity peaked at early night (c.a. 2200-2300 h) while cardiac acetylcholine synthesis peaked at the afternoon (c.a. 1700-1900 h). Old rats exhibited a significant decrease of rhythm amplitude and increase of mean values in tyrosine hydroxylase activity in autonomic ganglia and adrenal medulla, and abolition of tyrosine hydroxylase rhythm in the heart. Twenty-four hour rhythmicity in acetylcholine synthesis was impaired or abolished in aged rats. Treatment of old rats with 10 or 100 microg melatonin generally augmented amplitude of rhythms and reinduced the nocturnal peak of acetylcholine synthesis in the hypogastric ganglion. Only the high melatonin dose significantly augmented rhythm amplitude of tyrosine hydroxylase activity (superior cervical and coeliac-superior mesenteric ganglia) and acetylcholine synthesis (superior cervical, stellate and coeliac-superior mesenteric ganglia) in young rats. The results indicate that the activity of the central oscillator, driven to the organs in part via the autonomic nervous system, deteriorates significantly with aging and that melatonin may restore partially such a deterioration.

Acetylcholine↗
PubMed2003

Differing patterns of neurotrophin-receptor expressing neurons allow distinction of the transient Frorieps' ganglia from normal DRG before morphological differences appear.

The Frorieps' ganglia are dorsal root ganglia (DRG) that form and then degenerate during normal embryonic development of amniotes. Their degeneration or survival has been shown to be modulated by modifying expression of Hox-family and other genes involved in pattern formation, and by the mesodermal microenvironment of the cranial somites in which they develop. In ovo application of the neurotrophin NGF partially rescues DRG2 from degeneration. To further examine the potential role of neurotrophins in the life cycle of Frorieps' DRG we have now quantified the numbers of neurons expressing neurotrophin receptors trkA and trkC in avian Frorieps' ganglia (DRG2) and normal cervical DRG (DRG5). We have found that the Frorieps' DRG are different from normal DRG in terms of the numbers of neurons expressing these receptors. trkC-expressing neurons are generally lacking in DRG2, this is the earliest (St 18, E2.5) described difference between DRG2 and normal DRG, preceding morphological differences between these ganglia that appear at St 20. The difference between DRG2 and DRG5 in terms of numbers of trkA-expressing neurons is evident only at later embryonic stages, where DRG2 contains a higher proportion of trkA neurons than normal cervical DRG. The few trkC+ neurons present late in DRG2 development are not concentrated in the VL portion of the ganglion, the zone where trkC+ neurons are generally found in normal DRG. We also find that DRG2 neurons are smaller than those of normal DRG, this is true for both trkA+ and trkC+ populations. These data together therefore suggest that the neurons that survive in the Frorieps' ganglia at later stages belong almost exclusively to the trkA-expressing DM class DRG neurons. We further find that the differences in the populations of trkA/trkC between DRG2 and DRG5 result from signals from the mesodermal microenvironment, since DRG arising in cranial somites transplanted caudally contain few trkC+ neurons and a higher proportion of trkA+ cells than contralateral controls.

Animals↗
PubMed2003

[Sympathetic dermatomes corresponding to T2 and T3 ganglia. A prospective study of 100 superior thoracic sympathicolytic procedures].

UNLABELLED: The autonomic nervous system adjusts sweating on the body's skin surface. The skin areas corresponding to the various sympathetic ganglia are not yet clearly defined. The purpose of this study was to define the skin areas corresponding to the T2 and T3 sympathetic ganglia. METHODS AND MATERIALS: We performed bilateral thoracic sympathicolysis endoscopically on the T2 and T3 ganglia of 50 patients with primary hyperhidrosis. All answered a questionnaire before surgery and at least two months later. The questionnaire asked about sweating at different points, but in order to estimate the cutaneous projection of T2 and T3 we only analyzed anhidrotic regions. RESULTS: Denervation resulted in anhidrotic hands (98.11%); axillas (73.58%); arms (39.62%); forehead (20.75%); chin, cheeks, neck and the nape of the neck (16.98%); sides of the chest (13.2%); front of the chest (7.54%); and back (1.88%). CONCLUSIONS: The territory influenced by the T2 and T3 sympathetic ganglia is more extensive than has been described by classical anatomical studies. The cutaneous area innervated by the sympathetic T2 and T3 ganglia extends to zones influenced by T1 in up to 20.75% of patients with primary hyperhidrosis.

Axilla↗
PubMed1997

Expression of fibroblast growth factor-2 and fibroblast growth factor receptor 1 messenger RNAs in spinal ganglia and sciatic nerve: regulation after peripheral nerve lesion.

In order to determine functional roles of basic fibroblast growth factor (FGF-2) in the peripheral nervous system we have analysed the expression of FGF-2 and FGF receptor 1 (FGFR1) in spinal ganglia and the sciatic nerve under normal conditions and after nerve crush using RNAse protection assay and in situ hybridization. In intact spinal ganglia, both FGF-2 and FGFR1 messenger RNAs are expressed, albeit at different levels. In situ hybridization identifies satellite cells as the source of FGF-2 and sensory neurons as the source of FGFR1 suggesting a paracrine mode of action of FGF-2 on sensory neurons. One day after crush lesion FGF-2 is significantly up-regulated in sensory ganglia L4-L6. Highest levels are found at day 7; control levels are approached after 28 days. FGFR1 messenger RNA, which is strongly expressed in intact spinal ganglia, displays no significant change after lesion. In the intact sciatic nerve, FGFR1 messenger RNA is detected at higher levels than FGF-2 messenger RNA. After injury, both transcripts display a time-dependent up-regulation in both the proximal and distal nerve stump. Schwann cells, as a putative source of the sciatic nerve-derived FGF-2, express both FGF-2 and FGFR1 messenger RNAs in vitro. The FGFR1 transcript level is increased in the presence of forskolin. FGF-2 does not affect expression of FGFR1 messenger RNA but stimulates its own expression. These results show that during peripheral nerve regeneration FGF-2 is up-regulated in both the crushed nerve and the respective spinal ganglia suggesting a possible physiological function of FGF-2 during the regeneration process.

Animals↗
PubMed1997

Position of the ventral pallidum in the rat prefrontal cortex-basal ganglia circuit.

The ventral pallidum receives major inputs from the nucleus accumbens, a striatal region related to the prefrontal cortex. The ventral pallidum, through its projections to the mediodorsal nucleus of the thalamus, has been considered as the main output structure of the prefrontal-basal ganglia circuits. However, as shown recently, the ventral pallidum also sends efferents to the subthalamic nucleus and the substantia nigra, suggesting that it could participate in intrinsic basal ganglia circuits. The aim of the present investigation was to determine the position of the ventral pallidum in the prefrontal-basal ganglia circuit originating from the prelimbic and medial orbital areas. Following injections of biocytin (an anterograde tracer) into the region of the core of the nucleus accumbens receiving excitatory inputs from the prelimbic and medial orbital areas, axonal terminal fields were observed in a delineated dorsal region of the ventral pallidum. When the biocytin injections were made into this ventral pallidal region, anterogradely labelled fibres were observed in both the dorsomedial substantia nigra pars reticulata and the medial subthalamic nucleus, but not in the mediodorsal nucleus of the thalamus. Confirming these anatomical observations, electrical stimulation of the core of the nucleus accumbens induced an inhibition of the spontaneous activity (D=34.9+/-13.3 ms, L=9.2+/-3.3 ms) in 46.5% of the ventral pallidal cells. Among these responding cells, 43% were antidromically driven from the subthalamic nucleus, 30% from the substantia nigra pars reticulata and only 6% from the mediodorsal nucleus of the thalamus. These data demonstrate that the region of the ventral pallidum involved in the prefrontal cortex-basal ganglia circuit originating from the prelimbic and medial orbital areas represents essentially a ventral subcommissural extension of the external segment of the globus pallidus since it exhibits similar extrinsic connections and functional characteristics. In conclusion, in this prelimbic and medial orbital channel, the ventral pallidum cannot be considered as a major output structure but is essentially involved in intrinsic basal ganglia circuits.

Animals↗
PubMed1999

Localization of central cannabinoid CB1 receptor messenger RNA in neuronal subpopulations of rat dorsal root ganglia: a double-label in situ hybridization study.

In situ hybridization histochemistry was used to show the distribution of messenger RNA for central cannabinoid CB 1 receptors in dorsal root ganglia of the rat. CB1 messenger RNA was highly expressed in neuronal subpopulations of rat dorsal root ganglia. The phenotypes of neurons that express messenger RNA for CB1 were subsequently examined by combining a 35S-labeled ribonucleotide probe for CB1 messenger RNA with digoxigenin-labeled riboprobes for preprotachykinin A (substance P precursor), alpha-calcitonin gene-related peptide and preprosomatostatin (somatostatin precursor) messenger RNAs. Qualitative examination revealed expression of CBI messenger RNA predominantly in medium-and large-sized cells distributed throughout the dorsal root ganglia. The majority of neurons expressing substance P messenger RNA were CB1 messenger RNA negative and smaller in size than the CB1 messenger RNA-positive cells. Only 13% of substance P messenger RNA-positive cells expressed CB1 messenger RNA. A similar degree of co-localization was observed with alpha-calcitonin gene-related peptide: 10% of cells expressing messenger RNA for this neuropeptide were CB1 messenger RNA positive. Co-localization of CB1 and somatostatin messenger RNAs was observed in less than 0.5% of somatostatin messenger RNA-positive cells. The data suggest that subpopulations of neurons in rat dorsal root ganglia are capable of synthesizing cannabinoid receptors and inserting them on terminals in the superficial dorsal horn. These findings provide anatomical evidence for cannabinoid modulation of primary afferent transmission. Although an anatomical basis for cannabinoid-mediated suppression of release of neurogenic peptides from nociceptive primary afferents is provided, our results demonstrate that the majority of CB messenger RNA-positive neurons in the dorsal root ganglia contain transmitters and/or neuromodulators other than the neuropeptides examined herein.

Animals↗
PubMed1999

Dopamine agonist-mediated rotation in rats with unilateral nigrostriatal lesions is not dependent on net inhibitions of rate in basal ganglia output nuclei.

Current models of basal ganglia function predict that dopamine agonist-induced motor activation is mediated by decreases in basal ganglia output. This study examines the relationship between dopamine agonist effects on firing rate in basal ganglia output nuclei and rotational behavior in rats with nigrostriatal lesions. Extracellular single-unit activity ipsilateral to the lesion was recorded in awake, locally-anesthetized rats. Separate rats were used for behavioral experiments. Low i.v. doses of D1 agonists (SKF 38393, SKF 81297, SKF 82958) were effective in producing rotation, yet did not change average firing rate in the substantia nigra pars reticulata or entopeduncular nucleus. At these doses, firing rate effects differed from neuron to neuron, and included increases, decreases, and no change. Higher i.v. doses of D1 agonists were effective in causing both rotation and a net decrease in rate of substantia nigra pars reticulata neurons. A low s.c. dose of the D1/D2 agonist apomorphine (0.05 mg/kg) produced both rotation and a robust average decrease in firing rate in the substantia nigra pars reticulata, yet the onset of the net firing rate decrease (at 13-16 min) was greatly delayed compared to the onset of rotation (at 3 min). Immunostaining for the immediate-early gene Fos indicated that a low i.v. dose of SKF 38393 (that produced rotation but not a net decrease in firing rate in basal ganglia output nuclei) induced Fos-like immunoreactivity in the striatum and subthalamic nucleus, suggesting an activation of both inhibitory and excitatory afferents to the substantia nigra and entopeduncular nucleus. In addition, D1 agonist-induced Fos expression in the striatum and subthalamic nucleus was equivalent in freely-moving and awake, locally-anesthetized rats. The results show that decreases in firing rate in basal ganglia output nuclei are not necessary for dopamine agonist-induced motor activation. Motor-activating actions of dopamine agonists may be mediated by firing rate decreases in a small subpopulation of output nucleus neurons, or may be mediated by other features of firing activity besides rate in these nuclei such as oscillatory firing pattern or interneuronal firing synchrony. Also, the results suggest that dopamine receptors in both the striatum and at extrastriatal sites (especially the subthalamic nucleus) are likely to be involved in dopamine agonist influences on firing rates in the substantia nigra pars reticulata and entopeduncular nucleus.

Animals↗
PubMed1999

Functional Na+/K+ pump in rat dorsal root ganglia neurons.

Steady-state Na+/K+ pump current (Ip) in isolated adult rat dorsal root ganglia neurons was studied to determine if the plasma membrane Na+/K+ pump activity is uniform across the population of dorsal root ganglia neurons. Cells were voltage-clamped at -40 mV and holding current (Ih) was recorded using whole-cell patch-clamp techniques under conditions that stimulate the Na+/K+ pump (60 mM intracellular Na+ and 5.4 mM extracellular K+). Ip was defined as the 1 mM ouabain-sensitive fraction of Ih. Data suggest the existence of three subpopulations of dorsal root ganglia neurons having mean steady-state Ip densities of 1.6+/-0.1, 3.8+/-0.2 and 7.5+/-0.4 pA/pF. Neurons with small Ip had an average soma perimeter of 95+/-3 microm, while neurons with medium and large Ip density had significantly larger soma sizes (131+/-8 and 141+/-7 microm, respectively). Neurons with a large Ip density had a significantly lower specific membrane resistance (Rm; mean 4.0+/-0.3 kohm x cm2) than neurons with medium or small Ip density (19+/-6 and 31+/-6 kohm x cm2, respectively). Regardless of these differences, in all groups of neurons Ip had a low sensitivity to ouabain (Ip half inhibition by ouabain was observed at 80-110 microM). These data suggest that the Na+/K+ pump site density and/or its activity is not uniform throughout the dorsal root ganglia neuron population; however, this non-uniformity does not appear to relate to the functional expression of the different alpha isoforms of the Na+/K+ pump. The major functional Na+/K+ pump in the dorsal root ganglia neuron plasma membrane appeared to be the low ouabain affinity (alpha1) isoform.

Animals↗
PubMed2001

p75NGFR immunoreactivity in normal prenatal human dorsal root ganglia.

The purpose of the present study was to examine immunohistochemically the expression of the low-affinity p75 nerve growth factor receptor in the dorsal root ganglia from 12 human fetuses (gestational ages, 10-24 weeks) located in three different spinal segments (cervical, thoracic, and lumbosacral), using a monoclonal mouse-antihuman low-affinity p75 nerve growth factor receptor antibody. The low-affinity p75 nerve growth factor receptor immunoreactivity was present within the dorsal root ganglia and the surrounding nerve fibers in all spinal segments at the different gestational ages examined. From 10 weeks of gestation, three different types of neuronal staining were observed: dorsal root ganglia neurons without low-affinity p75 nerve growth factor receptor immunoreactivity (classified as type I neurons), neurons displaying weak low-affinity p75 nerve growth factor receptor immunoreactivity (classified as type II neurons), and neurons manifesting intense low-affinity p75 nerve growth factor receptor immunoreactivity (classified as type III neurons). The distribution of the three types of neurons in the dorsal root ganglia was identical in the three spinal segments and did not change between 10 and 24 weeks of gestation. This study provides the first demonstration of the low-affinity p75 nerve growth factor receptor immunoreactivity in the dorsal root ganglia from human fetuses at different gestational ages.

Female↗
PubMed2002

Metabolite alterations in basal ganglia associated with methamphetamine-related psychiatric symptoms. A proton MRS study.

Following the chronic use of methamphetamine, some individuals experience psychosis and anxiety. One reason may be the persistence of metabolite abnormalities in the brain of currently abstinent former methamphetamine users. In this study, N-acetylaspartate (NAA), creatine plus phosphocreatine (Cr+PCr), and choline-containing compound (Cho) levels were measured in the left and right basal ganglia using proton magnetic resonance spectroscopy (MRS) in 13 abstinent methamphetamine users and 11 healthy comparison subjects with no history of illicit drug use. The methamphetamine users showed a significantly reduced Cr+PCr/Cho ratio in the bilateral basal ganglia compared with the healthy comparison subjects. Furthermore, the reduction in the Cr+PCr/Cho ratio was significantly correlated with the duration of methamphetamine use and with the severity of residual psychiatric symptoms. NAA/Cho ratios in the bilateral basal ganglia did not significantly differ between methamphetamine users and comparison subjects. These findings suggest that protracted use of methamphetamine may cause metabolite alterations in the basal ganglia. Furthermore, residual psychiatric symptoms may be attributable to the metabolite alterations in the basal ganglia.

Adult↗