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PubMed1998

Morphological and cytological ontogenesis of the ampullae of lorenzini and lateral line canals in the Oman shark, Iago omanensis Norman 1939 (Triakidae), from the Gulf of Aqaba, Red Sea.

The Oman shark, Iago omanensis, is a small, placental viviparous species encountered in great numbers in the deeper waters of the Gulf of Aqaba, Red Sea. It reproduces year-round, providing an opportunity to study ontogenesis of organ systems at various stages of development. This study examines the morphological and cytological development of the mechanoreceptive lateral line (LL) system and the electrosensory Ampullae of Lorenzini. Female I. omanensis were collected bimonthly from the Gulf of Aqaba at depths of 300-800 m and sacrificed with an overdose of MS222. Their uteri were dissected and the embryos separated and fixed for light and electron microscopy. A total of 260 embryos of varying dimensions were studied. The first primordia of neuroectodermal LL neuromasts are seen in embryos of 18 mm TL. These then sink into the dermis, ripen, and develop tubuli that join to form the LL canal systems, especially developed on the head. In contrast, the primordia of Ampullae of Lorenzini start out as groups of embryonic cells situated subdermally. In embryos of 24-26 mm TL initially they develop into tubuli. With growth, the ampullar alveoli gradually widen at their ends to form the sensory epithelium. The ampullar tubuli elongate, bringing the alveoli to sites over the rostrum and head, where the ampullar capsules are formed. The presynaptic electrosensory cells are attached to afferent neural extensions forming sensory rami which extend, as in adult sharks, to the dorsal nucleus in the medulla. In preterm juveniles of 150-160 mm TL, the LL system and the Ampullae of Lorenzini are fully developed cytologically. The results of this study support the hypothesis that the LL system and electrosensory Ampullae of Lorenzini develop as separate modalities and that their structural similarity is due to the origin from the embryonic neuroectoderm. The dichotomy of their evolution occurred in very early ancestry as an ecomorphological adaptation to different sensory functions.

Animals↗

PubMed1999

50 Hz magnetic field exposure influence on human performance and psychophysiological parameters: two double-blind experimental studies.

Two double-blind studies were performed to examine magnetic field (MF) exposure effects and to determine the impact of temporal variation (continuous vs. intermittent exposure) of 100 mu T(rms) 50 Hz MF diurnal exposure on psychological and psychophysiological parameters in healthy humans. Three cephalic exposure sessions of 30-min, i.e., sham, continuous, and intermittent (15 s ON/OFF cycles) MF conditions, were involved. Each subject participated in all sessions, which were spaced at 1-wk intervals. In each session, mood ratings and performance measures were obtained before, during, or after exposure and several electrophysiological data (event-related brain potentials [ERP]) were recorded after each exposure session. These criteria were chosen to evaluate sensory functions as well as automatic and voluntary attentional processes. In experiment 1, 21 healthy male volunteers (20 to 27 years of age) were studied. Ten subjects were exposed at 13:30 h, and 11 subjects were exposed at 16:30 h. Statistically significant changes in the amplitude of ERP were observed after MF exposure in the dichotic listening task, indexing selective attention processes. Eighteen of the 21 original male volunteers took part in experiment 2, undertaken to better understand the results related to information processing involved in selective attention and control for ultradian rhythmicity. Exposure time for all the subjects was at 13:30 h. The analysis of the data again revealed significant amplitude changes of the ERP recorded in the dichotic listening task. Moreover, they demonstrated ERP latency and reaction time slowing in the oddball paradigm, a visual discrimination task after real MF exposure. These results also indicate that a low level 50 Hz MF may have a slight influence on event-related potentials and reaction time under specific circumstances of sustained attention.

Activity Cycles↗

PubMed2001

IDA-1, a Caenorhabditis elegans homolog of the diabetic autoantigens IA-2 and phogrin, is expressed in peptidergic neurons in the worm.

The closely related mammalian proteins IA-2 and phogrin are protein tyrosine phosphatase-like receptor proteins spanning the membrane of dense core vesicles of neuroendocrine tissues. They are of interest as molecular components of the secretory machinery and as major targets of autoimmunity in type I diabetes mellitus. The Caenorhabditis elegans genome has a single copy of an IA-2/phogrin homolog ida-1 III (islet cell diabetic autoantigen), which encodes the ida-1 (B0244.2) gene product as a series of 12 exons over a 10-kb region of chromosome III. The full-length sequence of the ida-1 cDNA encoded a 767-amino acid type 1 transmembrane protein of 87 kDa. The PTP catalytic site consensus sequence of IDA-1, like IA-2 and phogrin, diverged and would not be active. Expression of green fluorescent protein (GFP) under the ida-1 gene promoter showed activity in a subset of around 30 neurons with sensory functions and the uv1 cells of the vulva in hermaphrodites. Males showed additional expression in male-specific neurons. In situ experiments in rat brain showing the distribution of IA-2 and phogrin suggested a complimentary and overlapping pattern compared with the proprotein convertases PC1 and PC2. In C. elegans, IDA-1-expressing cells comprised a subset of those expressing the PC2 homolog KPC-2 (C51E3. 7), consistent with IDA-1 being a component of neuropeptide-containing dense core vesicles. The results support the hypothesis that C. elegans IDA-1 is the functional homolog of IA-2 and phogrin in mammals. Analysis of the function of IDA-1 should contribute to our understanding of the function of these proteins in signal transduction, vesicle locomotion, and exocytosis.

Amino Acid Sequence↗

PubMed2000

Nerve fiber composition of the intracranial portion of the oculomotor, trochlear, and abducens nerves in the sheep.

In the present investigation, the fiber content and the diameter spectra of the intracranial portion of the three oculomotor nerves (oculomotor, trochlear, and abducens nerves) were analysed in sheep by light and electron microscopy. It was determined that up to 14.98% of fibers in the oculomotor nerve, 17.01% in the trochlear nerve, and 11.87% in the abducens nerve were unmyelinated. The myelinated fibers showed a bimodal distribution in their size spectrum in all three nerves, with a majority of large myelinated axons, but a considerable proportion of small myelinated fibers, as well. The sensory function of the unmyelinated fibers present in the three oculomotor nerves is discussed also on the basis of our previous morphofunctional investigations.

Abducens Nerve↗

PubMed2001

Sexual arousal and orgasm in women: effects of spinal cord injury.

Sexual disorders are common in women; however, the neurological basis of female sexual response has not been adequately investigated. This information is necessary to characterize the impact of various neurological disorders on sexual arousal in women and to develop appropriate management strategies for sexual dysfunction. To assess the spinal mediation of sexually stimulated genital vasocongestion in women, we conducted two laboratory-based, controlled analyses: (1) of women's genital, subjective, and autonomic responses to audiovisual erotic and audiovisual erotic combined with manual genital stimulation; and (2) of women's ability to achieve orgasm. Subjects included 68 premenopausal women with spinal cord injuries (SCIs) and 21 able-bodied, age-matched controls. Results indicated that preservation of sensory function in the T11-L2 dermatomes is associated with psychogenically mediated genital vasocongestion. Less than 50% of women with SCIs were able to achieve orgasm, compared with 100% of able-bodied women (p = 0.001). Only 17% of women with complete lower motor neuron dysfunction affecting the S2-S5 spinal segments were able to achieve orgasm, compared with 59% of women with other levels and degrees of SCIs (p = 0.048). Time to orgasm was significantly increased in women with SCIs compared with able-bodied controls (p = 0.049). Independent raters were unable to differentiate between subjective descriptions of orgasm from SCI women compared with controls. This information should be used when counseling women with spinal dysfunction about their sexual potential.

Adult↗

PubMed2001

Discriminating mild parkinsonism: methods for epidemiological research.

Methods for the efficient and accurate detection of parkinsonism are essential for epidemiological studies. We sought to determine whether parkinsonism could be detected by a neurologist from a videotaped assessment and whether neurobehavioral methods (motor, cognitive, and sensory) discriminated between patients with Parkinson's disease (PD) and controls. Fifteen patients with mild PD (Hoehn and Yahr I-III) were compared to 15 age-, sex-, and education- matched controls. Each participant underwent a videotaped neurological examination (based on the Unified Parkinson's Disease Rating Scale, UPDRS), administered by a trained technician, and reviewed by a neurologist, as well as a series of neurobehavioral tests. The neurologist identified PD patients with 86% sensitivity and 100% specificity. Among the neurobehavioral tests, finger tapping, combined with one or more among olfaction, visual contrast sensitivity, or Paired Associates Learning, correctly classified 90%, or more, of subjects. Individual psychological tests did not discriminate reliably between groups. We conclude that videotaped assessments of parkinsonism or objective tests of motor and sensory function can accurately detect patients with PD. Both approaches have potential for identifying PD cases, but the latter may be more efficient for screening.

Cognition Disorders↗

PubMed2004

Unilateral nerve injury produces bilateral loss of distal innervation.

There are no known anatomical connections between neurons that innervate homologous right and left body parts. Nevertheless, some patients develop bilateral abnormalities after unilateral injury, a phenomenon often unrecognized and not yet characterized. Therefore, we examined in rats the effects of ligating and cutting one tibial nerve on sensory function and on density of innervation in hind paws contralaterally as well as ipsilaterally to the injury, at times between 1 day and 5 months after surgery. Punches removed from tibial- or sural-innervated planter paw skin were immunolabeled to quantitate epidermal nerve endings. Naive and sham-operated rats provided controls. Axotomized rats had near-total loss of PGP9.5(+) innervation within ipsilateral tibial-innervated skin at all time-points. Adjacent ipsilateral sural-innervated skin had persistent hyperalgesia without denervation, and robust axonal sprouting at 5 months after surgery. Contralesional hind paws lost 54% of innervation in tibial-innervated epidermis starting 1 week after surgery and persisting throughout. Contralesional sural-innervated skin had neither neurite loss nor sprouting. These results imply that unilateral nerve injury can cause profound, long lasting, nerve-branch-specific loss of distal innervation contralaterally as well as ipsilaterally. They discredit the practice of using tissues contralateral to an injury to provide normative controls and suggest the possibility of rapid, transmedian postinjury signals between homologous mirror-image neurons.

Animals↗

PubMed1990

A clinical triad to diagnose paraneoplastic retinopathy.

Two elderly men developed photosensitivity and light-induced glare, transient visual symptoms, and progressive visual loss several months before small cell carcinoma of the lung was discovered. Both patients had impaired visual acuity and color vision, ring scotomas, and attenuated retinal arteriole caliber. Electroretinography demonstrated abnormal cone and rod-mediated responses. Antiretinal antibodies were identified in their serum. Their visual sensory function improved following therapy with immunosuppressive agents. The triad of photosensitivity, ring scotomatous visual field loss, and attenuated retinal arteriole caliber should alert one to a paraneoplastic disorder affecting the retina.

Adenocarcinoma↗

PubMed1997

The clinical syndrome of early-life bilateral hippocampal sclerosis.

Four infants had bilateral hippocampal sclerosis by magnetic resonance scans, including oblique coronal fast spin echo images of the temporal lobes; [18F]fluorodeoxyglucose-positron emission tomographic scans, done in 2 infants, showed isolated bilateral anterior temporal lobe hypometabolism. All had epilepsy with episodes of status epilepticus. Despite adequate motor and sensory functions, all failed to develop language (or lost attained language), social skills, and complex purposive or adaptive activity, even after epilepsy was controlled. Bilateral hippocampal dysfunction in early life appears to be associated with a profound failure of cognitive capacities, including language learning and learning of complex social and adaptive skills in general. The deficits correspond to the cognitive deficits of severe infantile autism. Hippocampal function, or more generally medial temporal lobe function, appears necessary for language learning in the infant, as well as for complex social and adaptive learning.

Brain Diseases↗

PubMed1976

Fine structure of tracheo-bronchial epithelial nerves of the cat.

The nerves in and immediately under the epithelial layer of the trachea and primary bronchi of the cat are studied with the electron microscope. The axons are unmyelinated and contain microtubules and mitochondria. Epithelial axons are observed throughout the entire epithelial layer, but, are usually concentrated in the basal area immediately above the basal lamina. Most axons are near the basal cells; others are in the vicinity of granulated cells or occur in the intercellular spaces between other columnar cells. A few of the epithelial axons are large and crowded with axoplasmic mitochondria. The possibility that some epithelial axons may have sensory functions is discussed.

Animals↗

PubMed1983

Quantitative assessment of neural development in human premolars.

The number of nerve fibers entering a tooth gives an indication of the tooth's capacity to perform a sensory function. Nerve fiber development was quantitated from cross sections of the apical portions of 49 erupted human premolars at various stages of root development and in subjects up to 71 years of age. Neural development was incomplete in immature teeth, greatly variable in young mature teeth, and complete in older teeth. Myelinated axons changed in number but not in size during tooth development. There were significantly fewer myelinated axons in teeth with open and parallel apical foramina than in older teeth. Unmyelinated axons did not change significantly in number with development but fewer large axons were found in older teeth. The number of unmyelinated axons enclosed in a single boundary lamina tended to be lower in older teeth. As a physiologic correlate, threshold responses to electrical stimulation were also determined prior to premolar removal. Threshold stimulation decreased significantly with apical foramen maturation. A significant negative correlation was found between the threshold stimulus and the number of myelinated axons in fully developed teeth, but not in immature teeth.

Adolescent↗

PubMed1987

Selective conservative and routine early operative treatment in acute limb ischaemia.

Arterial thrombo-embolectomy is often unsuccessful in those patients with acute limb ischaemia that have peripheral arteriosclerosis. During this study, conservative heparin treatment and, when needed, delayed surgery was employed in acute limb ischaemia when the ischaemia was less severe as judged by assessment of distal motor and sensory functions, regardless of the presumed aetiology of the acute ischaemia. The results are compared with those during a preceding period, when the routine treatment was emergency thrombo-embolectomy. The emergency operation rate was reduced to 49 per cent. There were overall fewer deaths with gangrene (8 per cent versus 18 per cent). In acute arterial thrombosis, more good results were obtained (76 per cent versus 47 per cent), whereas results were unchanged in embolic cases despite the reduced emergency operation rate. This study suggests that the choice of initial treatment of patients with acute limb ischaemia may be based on the severity of the ischaemia, and that patients with less severe acute ischaemia benefit from initial conservative heparin treatment.

Acute Disease↗

PubMed1995

Clinical and physiological evaluation of anorectal eversion during restorative proctocolectomy.

Fifty patients had a restorative proctocolectomy with stapled end-to-end ileoanal anastomosis by the eversion technique. Median (interquartile range) maximum resting anal pressure was 90 (73-116) cmH2O before restorative proctocolectomy and 71 (51-88) cmH2O 1 year after surgery (P < 0.001). Median maximum squeeze pressure was 141 (110-185) cmH2O before surgery and 146 (118-186) cmH2O 1 year after surgery (P not significant). Median thresholds for sensation in the lower third of the anal canal before and 1 year after surgery were 5.3 and 7.1 mA, respectively (P = 0.006). One year after restorative proctocolectomy, all patients were continent, although two experienced leakage of mucus requiring a pad. Forty-two patients (84 per cent) could discriminate between faeces and flatus. Eversion of the anorectum during restorative proctocolectomy impairs the motor and sensory functions of the anal sphincter. Most patients achieved satisfactory anal continence, however, despite these physiological changes.

Adolescent↗

PubMed2004

Sacral nerve stimulation for faecal incontinence in the UK.

BACKGROUND: Sacral nerve stimulation (SNS) is an effective therapy for faecal incontinence. Published studies derive largely from single centres and there is a need to determine the broader applicability of this procedure. METHODS: Prospective data were collected for all patients undergoing SNS in the UK. Records were reviewed to determine the outcome of treatment. RESULTS: In three UK centres 59 patients underwent peripheral nerve evaluation, with 46 (78 per cent) proceeding to permanent implantation. Of these 46 patients (40 women) all but two had improved continence at a median of 12 (range 1-72) months. Faecal incontinence improved from a median (range) of 7.5 (1-78) to 1 (0-39) episodes per week (P < 0.001). Urgency improved in all but five of 39 patients in whom ability to defer defaecation was determined, improving from a median of 1 (range 0-5) to 10 (range from 1 to more than 15) min (P < 0.001). Maximum anal squeeze pressure and sensory function to rectal distension changed significantly. Significant improvement occurred in general health (P = 0.024), mental health (P = 0.008), emotional role (P = 0.034), social function (P = 0.013) and vitality (P = 0.009) subscales of the Short Form 36 health survey questionnaire. There were no major complications. One implant was removed. CONCLUSION: SNS is a safe and effective treatment, in the medium to long term, for faecal incontinence when conservative treatment has failed.

Adult↗

PubMed2002

Pituitary adenylate cyclase-activating peptide in the rat central nervous system: an immunohistochemical and in situ hybridization study.

In the present study the localization of pituitary adenylate cyclase-activating peptide (PACAP)-expressing cell bodies and PACAP projections were mapped in the adult rat brain and spinal cord by using immunohistochemistry and in situ hybridization histochemistry. A widespread occurrence of PACAP-containing cell bodies was found, with the greatest accumulation in several hypothalamic nuclei and in several brainstem nuclei, especially the habenular nuclei, the pontine nucleus, the lateral parabrachial nucleus (LPB), and the vagal complex. PACAP was also present in cell bodies in the olfactory areas, in neocortical areas, in the hippocampus, in the vestibulo- and cochlear nuclei, in cell bodies of the intermediolateral cell column of the spinal cord and in Purkinje cells of the cerebellum, in the subfornical organ, and in the organum vasculosum of the lamina terminalis. An intense accumulation of PACAP-immunoreactive (-IR) nerve fibers was observed throughout the hypothalamus, in the amydaloid and extended amygdaloid complex, in the anterior and paraventricular thalamic nuclei, in the intergeniculate leaflet, in the pretectum, and in several brainstem nuclei, such as the parabrachial nucleus, the sensory trigeminal nucleus, and the nucleus of the solitary tract. PACAP-IR nerve fibers were also found in the area postrema, the posterior pituitary and the choroid plexus, and the dorsal and ventral horn of the spinal cord. The widespread distribution of PACAP in the brain and spinal cord suggests that PACAP is involved in the control of many autonomic and sensory functions as well as higher cortical processes.

Animals↗

PubMed2004

Histaminergic neurons in the central and peripheral nervous system of gastropods (Helix, Lymnaea): an immunocytochemical, biochemical, and electrophysiological approach.

Distribution, chemical-neuroanatomy, concentration, and uptake-release properties of histamine (HA)-containing neurons and the possible physiological effects of HA in the central and peripheral nervous system of the pulmonate snails, Helix pomatia and Lymnaea stagnalis, are described. In the CNS of both species, the distribution pattern of HA-immunoreactive (HA-IR) neurons was similar. In both species the majority were located in the buccal, cerebral, and pedal ganglia. In Helix, approximately 400 HA-IR neurons were seen, whereas in Lymnaea approximately 130 labeled cells were visualized. The neuropils, connectives, commissures, several peripheral nerves, and a part of the peripheral tissues (lip and foot of both species and the upper tentacles of Helix) were innervated by HA-IR elements. Numerous sensory cells were found in the tentacles, lip, and statocysts. The HA concentration values assayed by HPLC ranged from 4.8 to 47.4 pmol/mg in the different central ganglia of Helix, and from 4.3 to 18.6 pmol/mg in Lymnaea CNS, whereas the peripheral tissues contained 0.33-1 pmol/mg HA in Helix and 0.26-0.46 pmol/mg in Lymnaea. In the Lymnaea CNS, a high-affinity (37.6 microM), single component 3H-HA uptake system was demonstrated. 3H-HA release evoked by either electrical stimulation or 100 mM K+ could be prevented in Ca2+-free physiological solution. Voltage-clamp experiments indicated specific changes caused by HA in the membrane conductance of identified central neurons of Helix and Lymnaea. Exogenously applied 10(-5) M HA resulted in the acceleration of locomotion (gliding by foot cilia) of Lymnaea. The findings suggest an important signaling role of HA, described here for the first time, in the nervous system of higher-order, pulmonate, gastropods, involving efferent, integrative, and sensory functions. The data can also be applied as a background for further specification of HA in the regulation of different behaviors in these species.

Animals↗

PubMed2004

Low density of membrane particles in auditory hair cells of lizards and birds suggests an absence of somatic motility.

Hair cells are the mechanoreceptive cells of the vertebrate lateral line and inner ear. In addition to their sensory function, hair cells display motility and thus themselves generate mechanical energy, which is thought to enhance sensitivity. Two principal cellular mechanism are known that can mediate hair-cell motility in vitro. One of these is based on voltage-dependent changes of an intramembrane protein and has so far been demonstrated only in outer hair cells of the mammalian cochlea. Correlated with this, the cell membranes of outer hair cells carry an extreme density of embedded particles, as revealed by freeze fracturing. The present study explored the possibility of membrane-based motility in hair cells of nonmammals, by determining their density of intramembrane particles. Replicas of freeze-fractured membrane were prepared from auditory hair cells of a lizard, the Tokay gecko, and a bird, the barn owl. These species were chosen because of independent evidence for active cochlear mechanics, in the form of spontaneous otoacoustic emissions. For quantitative comparison, mammalian inner and outer hair cells, as well as vestibular hair, cells were reevaluated. Lizard and bird hair cells displayed median densities of 2,360 and 1,880 intramembrane particles/microm2, respectively. This was not significantly different from the densities in vestibular and mammalian inner hair cells; however, it was about half the density in of mammalian outer hair cells. This suggests that nonmammalian hair cells do not possess high densities of motor protein in their membranes and are thus unlikely to be capable of somatic motility.

Animals↗

PubMed1981

Immunohistochemical localization of enkephalin in the central nervous system and pituitary of the lizard, Anolis carolinensis.

The topographical distribution of enkephalin in the central nervous system of the lizard, Anolis carolinensis, has been studied by the immunoperoxidase technique with antiserum to leucine-enkephalin. Immunoreactive enkephalin perikarya, fibers and probably terminals are widely distributed throughout the central nervous system, which agrees well with the distribution of enkephalins in the mammalian brain. Enkephalin-containing perikarya are found in the subpallium (septum, nucleus accumbens, striatum, amydgala), preoptic and hypothalamic region, ventromedial nucleus and ventromedial area of thalamus, pretectal geniculate nucleus and posterodorsal nucleus of pretectum, nucleus of the lateral lemniscus, locus ceruleus, spinal trigeminal nucleus, nucleus of the solitary tract, medial parvocellular nucleus, and dorsal horn of the spinal cord. Enkephalinergic fibers and terminals are found in the above-mentioned areas as well as in the pallium (medial and dorsal cortex, dorsal ventricular ridge), dorsomedial and anterior dorsolateral nucleus of the thalamus, habenula, nucleus of the stria medullaris, torus semicircularis, mesencephalic tegmental area, interpeduncular nucleus, mesencephalic trigeminal nucleus, central gray, reticular formation, raphe nucleus, substantia nigra, isthmus region, and nucleus of the trapezoid body. Enkephalinergic pathways appear to exist between the septum and the medial cortex, nucleus accumbens and nucleus of the lateral olfactory tract, striatum and certain mesencephalic structures, hypothalamus and tegmentum, and between nucleus of the lateral lemniscus and torus semicircularis. In the pituitary, cells of the pars intermedia, and certain cells of the rostral pars distalis also show immunoreactivity to enkephalin antiserum. The distribution of enkephalin immunoreactivity throughout the hypothalamus and in the median eminence suggests involvement in neuroendocrine regulation. Presence of enkephalin in many extrahypothalamic brain areas indicates its important role in various sensory functions and in behavioral and autonomic integration.

Animals↗