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Results for “sensory function”

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PubMed1984

Effects of an intrathecal dopamine agonist, apomorphine, on thermal and chemical evoked noxious responses in rats.

The thermal cutaneous evoked tail flick and hot plate nociceptive responses as well as the chemical visceral elicited acetic acid writhing response were determined in rats following lumbar intrathecal administration of the dopamine (DA) agonist apomorphine. Apomorphine failed to influence tail flick latency even at high doses (660 nmol). In contrast, intrathecal apomorphine (33-330 nmol) produced a dose-dependent increase of the hot plate and acetic acid writhing responses, which was antagonized by the prior intrathecal administration of cis-flupenthixol (a DA receptor antagonist). Intrathecal pretreatment with either trans-flupenthixol (the inactive stereoisomer of cis-flupenthixol), methysergide, phentolamine or naloxone did not antagonize the apomorphine-induced increase of hot plate response latency. Intrathecal apomorphine did produce an increase of tail flick latency following pretreatment with methysergide and phentolamine, however. Intraventricular administration of apomorphine (82.5-165 nmol) had no influence on either tail flick or hot plate response latencies. The present data provide evidence for the modulatory role of apomorphine on spinal afferent sensory functions. It is suggested that a spinal DA receptor population has an inhibitory effect on noxious input to the spinal cord.

Afferent Pathways↗

PubMed1985

Immunocytochemical localization of glial fibrillary acidic protein (GFAP) in the area postrema of the cat. Light and electron microscopic study.

Glial fibrillary acidic protein (GFAP) was demonstrated in the cytoplasm and processes of ependymal cells and astroglial components of the area postrema of the cat. These observations differ from the findings in the ependyma of the ventricular cavities which are consistently negative for the protein. Since some studies have suggested sensory functions of the glial cells in this emetic chemoreceptor trigger zone, a careful consideration of morphological and biochemical attributes of these cells seems appropriate.

Animals↗

PubMed1985

Localization of [3H]nitrobenzylthioinosine binding sites in rat spinal cord and primary afferent neurons.

The distribution of [3H]nitrobenzylthioinosine ([3H]NBI) binding to nucleoside transport sites in rat spinal cord and spinal roots was examined using membrane binding and autoradiographic techniques. A single class of high affinity binding sites having dissociation constants (KD) between 0.42 +/- 0.05 and 0.088 +/- 0.012 nM was observed in dorsal and ventral spinal cord and their associated roots. The maximal number of binding sites (Bmax) in dorsal and ventral spinal cord was 110.1 +/- 7.1 and 73.6 +/- 7.5 fmol/mg protein, respectively. The highest levels of [3H]NBI binding were found in the dorsal grey matter of the cervical and lumbar enlargements. Autoradiographic studies showed that [3H]NBI sites were especially concentrated in the substantia gelatinosa of the dorsal spinal cord and the nucleus caudalis of the spinal trigeminal nucleus. The level of these binding sites in dorsal roots was nearly 4 times that observed in ventral roots; 98.5 and 23.0 fmol/mg protein, respectively. Adult animals depleted of unmyelinated sensory fibers by neonatal capsaicin treatment showed significantly reduced numbers of [3H]NBI sites (35%) in dorsal roots but not ventral roots, while KD values were unaffected. These results indicate that [3H]NBI sites are enriched in areas of the spinal cord and brainstem which subserve sensory functions and that these sites are located, in part, on unmyelinated primary afferent fibers.

Adenosine Deaminase↗

PubMed1986

The neuroanatomical basis for the protopathic sensibility of the human glans penis.

The human glans penis is covered by stratified squamous epithelium and a dense layer of connective tissue equivalent to the dermis of typical skin. Rete ridges of the epidermis are irregular and vary in height depending on location, age, and presence or absence of a foreskin. The papillary layer of the dermis blends into and is continuous with the dense connective tissue forming the tunica albuginea of the corpus spongiosum of the glans penis. The most numerous nerve terminals are free nerve endings (FNEs) present in almost every dermal papilla, as well as scattered throughout the deeper dermis. FNEs are characterized by an incomplete Schwann cell investment, and contain irregularly scattered neurofilaments and neurotubules, clusters of mitochondria, vesicles of variable size and various inclusions. The ratio of FNEs to corpuscular receptors is approximately 10:1 and a similar ratio of small to large axons is seen in dermal nerves. Genital end bulbs are present throughout the glans, but are most numerous in the corona and near the frenulum. The unique corpuscular receptor of the glans penis consists of axon terminals that at an ultrastructural level resemble a tangled skein of FNEs. Simple, Pacinian and Ruffini corpuscles were occasionally identified predominantly in the corona glandis. Epidermal Merkel nerve endings and other types of mechanoreceptors typically found in primate glabrous skin (lip or digit) are not present. Rarely, dermal Merkel cells have been identified associated with genital end bulbs. The abundance of FNEs in isolated as well as corpuscular form can be correlated with the embryogenesis and known neurophysiologic and psychophysical parameters of sensory function of the glans penis. Finally, the divergence in reported values for the threshold of tactile and painful stimuli when applied to glabrous skin of fingertip and glans penis can be considered as an example of dissociated sensibility. The anatomical basis for this dissociation is the abundance of FNEs and absence of Merkel terminals and typical Meissner corpuscles in the covering of the glans, and the converse in glabrous skin of the digit.

Adolescent↗

PubMed1986

Putative cholinergic interneurons in the optic tectum of goldfish.

We have demonstrated that a significant fraction of cells in layer 1 of goldfish optic tectum are immunoreactive for choline acetyltransferase. These cells constitute 4-7% of type XIV cells, which are thought to be intrinsic neurons and represent 95% of all tectal cells. The number of immunoreactive type XIV cells is unchanged following short-term enucleation. The possible integrative role of these putative cholinergic neurons is discussed in relation to sensory functions of the optic tectum.

Animals↗

PubMed1989

Distribution of choline acetyltransferase immunopositive structures in the rat brainstem.

The distribution of neurons, fibers and terminal fields in rat brainstem displaying positive immunoreactivity to a polyclonal antiserum to human placental choline acetyltransferase (ChAT) is described. The antiserum was used at the high dilution of 1:10,000 and was coupled with a sensitive detection system using the nickel ammonium sulfate intensification method. In addition to previously described ChAT immunopositive groups of large cells in the cranial motor nuclei, and the parabrachial and reticular complexes, many small or medium size, weakly immunopositive neurons were identified. Some of these appeared in structures in the region of the fourth ventricle, including the area postrema. Others were in structures associated with the superior olivary complex, including the lateral superior olive, and the medioventral, lateroventral and superior periolivary nuclei. Scattered, weakly positive cells were seen in numerous other structures, including the ventral tegmental area of Tsai, central gray, superior colliculus, spinal nucleus of nerve 5, dorsal cochlear nucleus and non-motor regions of the spinal cord. The prominent ascending fiber tract of the laterodorsal tegmental pathway was traceable from the parabrachial area to the subgeniculate region of the thalamus. Prominent terminal fields were seen in a number of brainstem structures, including the superior colliculus, pontine nuclei, anterior pretectal nucleus, interpeduncular nucleus and spinal nucleus of nerve 5. The association of small ChAT positive cells and terminal fields with many sensory structures suggests a significant cholinergic participation in the physiology of sensory function.

Animals↗

PubMed1994

Nitric oxide synthase-immunoreactive nerve fibers in the nasal mucosa of the rat.

An immunohistochemical study was performed to detect the localization of nitric oxide synthase (NOS) in the rat nasal mucosa by light and electron microscopy. NOS-immunoreactive nerve fibers were observed around blood vessels and seromucous glands. They were found in the subepithelial layer and even within the epithelium. But no NOS-immunoreactivity was found in the olfactory neuroepithelium. Electron microscopy showed that NOS-immunoreactive nerve profiles were in close contact with the cytolemma of respiratory epithelial cells and acinar cells of seromucous glands. NOS-immunoreactive axon varicosities were located at a considerable distance from the smooth muscle of arterioles and small veins as well as the endothelial cells of venules and capillaries. We confirmed that NOS-containing nerves innervated the epithelium, blood vessels and seromucous glands of the nasal mucosa. These findings, collectively, suggested the possibility that nitric oxide participated in the sensory function of the epithelium, the secretory activities of the nasal gland, and the regulation of vascular tone and vascular permeability in the nasal mucosa.

Amino Acid Oxidoreductases↗

PubMed1995

Nerve growth factor facilitates conditioned taste aversion learning in normal rats.

Chronic intracerebroventricular (i.c.v.) infusion of 3.2 micrograms/day of nerve growth factor (NGF) in normal rats elevated choline acetyltransferase (ChAT) activity of the striatum, medial septum, and basal forebrain and improved performance of a conditioned taste aversion (CTA) task. Relative to bovine serum albumin (BSA) or Cytochrome C treatments, NGF treatment facilitated acquisition and prolonged extinction of a lithium chloride (LiCl)-induced saccharin aversion. This facilitation was evident at saccharin/LiCl intervals ranging up to 1 h. Also, NGF treatment did not increase reactivity to LiCl-induced illness and neither shifted detection thresholds nor altered hedonic reactions to taste stimuli, indicating that NGF did not produce simple changes in sensory function. NGF treatments that elevate ChAT also facilitate memory of CTA in normal, adult rats.

Animals↗

PubMed1995

Direct evidence for the link between monoaminergic descending pathways and motor activity. I. A study with microdialysis probes implanted in the ventral funiculus of the spinal cord.

Monoaminergic projections to the spinal cord are involved in the modulation of motor, autonomic, and sensory functions. More specifically, the increase of electrical activity of serotonergic neurons in raphe obscurus has been correlated with locomotion in treadmill-trained cats [Jacobs, B.L. and Fornal, C., Trends Neurosci., 9 (1993) 346-352]. In order to test the direct correlation between locomotion and the release of monoamines, microdialysis probes were permanently implanted for 45 days into the ventral funiculus of the spinal cord (white matter) of adult rats. Eight days after implantation, these rats were subjected to an endurant exercise on a treadmill, and dialysis sessions were organized in such a way that microdialysate samples of 15 min duration were collected during pre-, per- and post-exercise periods. Measurements of serotonin, 5-hydroxyindoleacetic acid, dopamine and 3-methoxy-4-hydroxyphenylethylglycol concentration in the extracellular space showed significant increases during locomotion when compared with both pre- and post-exercise values. Histological analysis shows that serotonergic axons were present close to the dialysis probe. These results demonstrate that the implantation of a microdialysis probe in the ventral funiculus, close to a potential target of monoaminergic projections, is a suitable technique for the collection of neuromediators released during spontaneous running.

Animals↗

PubMed1986

Upper limb motor and sensory recovery after multiple proximal nerve injury in children: a long term review in five patients.

Five children who had sustained multiple proximal upper limb nerve injury were reviewed at 18 months to 3 1/2 years after primary repair had been carried out. The findings show that nerve regeneration occurred significantly more rapidly than in adults, with good return of motor and sensory function to the hand, resulting in each of the patients having a useful, painfree and functionally capable upper limb. In two of the cases, the limb had been completely severed. The findings support the view that primary repair of severed proximal nerves in this age group--even in avulsion type injuries--can give good results.

Arm Injuries↗

PubMed1980

Components of the movement-related cortical potential and their scalp topography.

In order to clarify the significance of the various components of the movement-related cortical potentials, scalp-recorded potential changes associated with voluntary, self-paced middle finger flexion and extension were studied by an opisthochronic averaging program in 14 normal right-handed subjects. Topographical study, based on 14 simultaneously recorded and averaged EEG channels, enabled us to identify at least 8 components; 4 pre-motion and 4 post-motion. The pre-motion components are the Beretischaftspotential (BP) (a symmetric early negative shift), NS'(-500 to -90) (a negative slope maximal over the contralateral precentral region and culminating in N-90 ipsilaterally), P-50 (corresponding to the pre-motion positivity, PMP), and N-10 (probably corresponding to the motor potential, MP). The post-motion components include N+50 (a sharp negative post-motion activity over the contralateral frontal region), P+90, N+160 (presumably representing sensory functions) and P+300 (a large positivity maximal over the contralateral precentral region but widely distributed).

Adolescent↗

PubMed1985

Tachykinin antagonists have potent local anaesthetic actions.

Contrary to what would have been expected, an antagonist of substance P (SP) [Arg5,D-Trp7,9]SP-(5-11) inhibited the neurogenic contraction of isolated guinea-pig hilus bronchi more readily than a contraction produced by exogenous SP. Furthermore, it has previously been shown that a tachykinin antagonist given intrathecally produced motor blockade as do local anaesthetic drugs. We therefore examined whether tachykinin antagonists had a depressant action on axonal neurotransmission. The compound action potential (APc) of the frog isolated sciatic nerve was suppressed in a concentration-dependent manner by the tachykinin antagonists [D-Pro2,D-Trp7,9]SP and [Arg5,D-Trp7,9]Sp-(5-11), both being about 4 times more potent than lidocaine. SP itself was without effect. Similarly in the rat isolated sciatic nerve [D-Pro2,D-Trp7,9]SP suppressed the APc. It was more potent in the A alpha- than in the C-fibres. SP did not affect conduction in either fibre type. In conscious guinea-pigs [D-Pro2,D-Trp7,9]SP injected adjacent to the sciatic nerve was found to block motor but not sensory functions of the limb. Thus, commonly used tachykinin antagonists, but not SP itself, have potent local anaesthetic properties. This should be considered when these agents are employed as pharmacological tools.

Action Potentials↗

PubMed1984

Reversible motor paralysis in rats after repeated electroconvulsive shock.

Repeated electroconvulsive shocks (ECS) delivered at brief (10 to 15 min) intervals through earclip electrodes, induced a reversible motor paralysis in 35% of treated rats. Paralysis was characterized by loss of locomotor activity without apparent loss of sensory functions. It occurred after 10 to 13 shocks regardless of whether stimulation was of subthreshold (40 to 60 mA) or suprathreshold (65 mA) intensity. This phenomenon may provide a useful animal model for the investigation of reversible injury to the spinal cord.

Animals↗

PubMed1985

Spinal cord contusion in the rat: morphometric analyses of alterations in the spinal cord.

Morphometric analyses were carried out on rat spinal cords which were injured by a weight drop technique. A 10-g weight was dropped 0.0, 2.5, 5.0, 7.5, 10.0, or 17.5 cm onto the dura which was exposed at the T8 vertebral level. Four weeks after injury, lesion volume, lesion length, and the dimensions of the tissue at the epicenter (lesion area, area of gray matter, and area of white matter) were measured and correlated with the height from which the weight was dropped and the results from tests of motor and sensory functional deficit. The results, based on linear regression analyses, indicated significant correlations between certain morphologic parameters (lesion volume, lesion length, and the area of gray and white matter at the epicenter) and both the height from which the weight was dropped and behavioral scores. Because the area of white matter at the epicenter is a very simple measurement which correlates well (r = 0.91) with behavioral outcome, this morphologic feature is a useful quantitative measure of the histopathologic consequences of spinal cord injury.

Animals↗

PubMed1989

Sweat gland reinnervation by sudomotor regeneration after different types of lesions and graft repairs.

Clinical and experimental investigations have shown that recovery of motor and sensory functions after a nerve lesion varies with the type of lesion and the repair technique. We report a study on regeneration of sudomotor axons to sweat glands (SGs) in the mouse paw following different sciatic nerve injury procedures: freezing, crushing, and sectioning. After sectioning, repair was by primary suture or by grafting with the resected section or with conduits of plastic or collagen. Successful regeneration was marked by the reappearance of SG reactivity to pilocarpine. After a freezing or crushing lesion, SGs activated by pilocarpine reappeared by 17 days postoperation and then increased progressively in number until the preoperative number of SGs were again active at 41 days. Cutting the nerve followed by primary repair resulted in a short delay and a significant deficiency in reinnervation. Results obtained with a graft of a segment of resected nerve were similar to primary repair after nerve section and better than when grafts of plastic or collagen tubes were used. This suggests that substances provided by the grafted nerve segment and the type of conduit provided play important roles in the regeneration of unmyelinated axons.

Animals↗

PubMed1977

Somatosensory evoked potentials. Diagnostic criteria and abnormalities in cerebral lesions.

In order to advance the practical application of measuring evoked cortical responses following electrical stimulation of the median nerve at the wrist (SEP) in clinical neurology, diagnostic criteria, consisting of the onset latency, peak latency and 2 indices of the first 3 negative components, and their left-and-right differences, were proposed and applied to 65 patients with cerebral lesions of various aetiologies. The criteria used were shown to be very useful in distinguishing between normal subjects and patients with cerebral lesions. The N1 and N2 components were related to the involvement of sensory pathways and were commonly associated with sensory impairment of all modalities or of deep proprioceptive and cortical modalities. The N3 component, on the other hand, was related to the presence of lesions and non-specific sites as well as non-specific symptomatology. SEP, judged by the present criteria, was shown to be useful as a complementary diagnostic aid in localizing the sites of lesions in sensory pathways and in evaluating sensory function, especially when used in combination with clinical symptomatology.

Adolescent↗

PubMed1983

Characterization of opioid peptides in guinea-pig heart and skin.

Using reverse phase HPLC separations, and assay of eluate fractions in the mouse vas deferens, extracts of heart and skin from guinea-pigs were shown to contain several species of opioid-active material in low amounts (3-20 pmol/g as [Met5]enkephalin). Immunohistochemical studies revealed in the heart a small number of enkephalin-immunoreactive nerve fibres, particularly in cardiac ganglia and some small cells (paraganglionic cells, APUD cells). In the skin, enkephalin-immunoreactivity was confined to Merkel cells. Cardiac and cutaneous opioid peptides may modulate peripheral cardiovascular and sensory functions.

Animals↗

PubMed1992

Pathological left-handedness revisited: dichotic listening in children with left vs right congenital hemiplegia.

Thirty-one children with right (n = 18) and left (n = 13) congenital hemiplegia were compared for incidence of hand- and foot-preference, eye-dominance, and familial sinistrality. In addition, they were tested with dichotic listening for correct reports of consonant-vowel syllables. The two groups of children were closely matched on IQ and sensory functioning. Children with mental retardation, or epileptic seizures were not included. The results showed that 89% of the left hemisphere impaired (LHI) children were left-handed, all of them preferred the left foot, and 72% were left eye-dominant. In the right hemisphere impaired (RHI) group, everyone (100%) preferred the right hand and foot, and 62% were right eye dominant. The dichotic listening results showed a significant right ear advantage (REA) in the RHI-group, and a significant left ear advantage (LEA) in the LHI-group. The results are discussed in the framework of pathological handedness and shifts in hemisphere control of language in children with early brain injury. It is argued that the homogeneous samples, except for the site of lesion, provides an interesting possibility to compare cognitive effects of left and right hemisphere impairment in children.

Adolescent↗