PubMed Health⌕ Search

Biomedical subjects

L D Aldes

Publications and source records attributed to L D Aldes.

27 records · Page 2Linked to original sources
PubMed1988

An electrographic characterization of ketamine-induced linguopharyngeal motor activity.

Ketamine-induced buccolinguopharyngeal motor activity was studied in rats visually and by means of force displacement transduction of tongue retrusions, electromyogram (EMG) of motor units of tongue muscles, and pressure transduction of swallowing acts. Each animal was anesthetized with an intramuscular injection of ketamine hydrochloride (100 mg/kg body weight). Through a tracheotomy the airway was intubated and the animal was mounted on a stereotaxic frame in a supine position for monitoring of the above parameters. Four varieties of events were demonstrated: (a) swallowing acts followed by tongue retrusion, (b) tongue retrusions in isolation, (c) tongue retrusions followed by swallowing events, and (d) swallowing events in isolation. All four types of events were vulnerable to intramuscular injection of haloperidol 0.75-2.5 mg/kg within 5 to 10 min and the suppression endured for at least several hours. We conclude that there is a parallel between ketamine-induced oral motor activity and neuroleptic-induced dyskinesia in that both are temporarily suppressed by neuroleptic drugs.

Animals↗
PubMed1986

Rat pineal exhibits two electrophysiological patterns of response to microiontophoretic norepinephrine application.

The spontaneous activity of 117 pineal units was recorded in urethane-anesthetized rats. The pineal units exhibited a wide range of firing rates of which 50% were on average slower than 14 spikes per second. Superior cervical ganglion (SCG) stimulation was studied in 76 pineal units; this stimulation caused excitation in 55% of the units. Microiontophoretic application of norepinephrine (NE) induced changes of firing rates in 61% of the pineal units tested. Two patterns of activity following NE microiontophoresis was observed: increase in firing rate (64%) and decrease in firing rate (36%). NE-induced excitation was observed only in those units excited by SCG stimulation. When NE and SCG stimulation were applied together, partial summation of the excitation induced by each one alone was observed. None of the units in which NE depressed the firing rate responded to SCG stimulation. Local application of propranolol blocked the excitation initiated by SCG stimulation as well as the excitation and the depression induced by NE microiontophoresis.

Action Potentials↗
PubMed1985

Organization of projections from the principal sensory trigeminal nucleus to the hypoglossal nucleus in the rat: an experimental light and electron microscopic study with axonal tracer techniques.

The organization of projections from the principal sensory trigeminal nucleus (PSN) to the hypoglossal nucleus (XII) in the rat was investigated at the light and electron microscopic level with retrograde and anterograde axonal tracer techniques. Microiontophoretic injection of horseradish peroxidase (HRP) into XII resulted in retrograde labeling of neurons confined to the dorsal one-third of the PSN. Labeled neurons were found bilaterally, although a clear preponderance for ipsilateral distribution was evident. Most labeled neurons were found in the medial one-third and caudal two-thirds of the PSN. Labeled neurons were large (30-50 micron), round-to-pear shaped multipolar cells with dendrites oriented primarily in the mediolateral direction. At the electron microscopic level, HRP reaction product was found throughout the cytoplasm of soma and processes of PSN projection neurons. The ultrastructural characteristics of these cells included a round, centrally placed nucleus and invaginated nuclear envelope, sparse Nissl bodies, numerous free ribosomes, mitochondria, lysosomes and Golgi complexes. Three to four main stem dendrites gradually tapered from the cell body and numerous synaptic terminals impinged upon soma and dendrites of labeled PSN neurons. Microiontophoretic injection of tritiated amino acids or HRP into the dorsal one-third of the PSN resulted in moderately dense terminal labeling in XII bilaterally, although mainly ipsilaterally. Terminal labeling was found diffusely throughout all regions of XII. Fibers descended the brainstem in the dorsolateral reticular formation and entered XII ventrolaterally. At the electron microscopic level, boutons containing HRP reaction product were found to synapse on dendritic processes in XII. Labeled boutons were characterized by clear, spherical vesicles and an asymmetrical postsynaptic density. The significance of these results are discussed in relation to oro-lingual motor behavior.

Animals↗
PubMed1984

A combined flat-embedding, HRP histochemical method for correlative light and electron microscopic study of single neurons.

A simple and reproducible method is described for studying the morphology of the same neuron at the light and electron microscopic level. This method utilizes horseradish peroxidase histochemistry and a recently described flat-embedding procedure wherein thin, aldehyde-fixed sections are placed in resin between glass microscope slides pretreated with dimethyldichlorosilane. The significance of these combined methodologies for correlative light and electron microscopic studies of single neurons is discussed.

Animals↗
PubMed1984

Does the interstitial nucleus of cajal project to the hypoglossal nucleus in the rat?

The present study sought to determine whether or not the hypoglossal nucleus receives direct afferent projections from the interstitial nucleus of Cajal. Results from anterograde and retrograde labeling experiments in the rat indicated that while projections from the interstitial nucleus of Cajal do not terminate within the hypoglossal nucleus, they do so among a small group of neurons located ventrolateral to the hypoglossal nucleus, the nucleus of Roller. These findings are discussed in relation to orolingual motor behavior.

Animals↗
PubMed1984

Synaptology of the hypoglossal nucleus in the rat.

The purpose of this study was to define the types and distribution of synaptic terminals in the hypoglossal nucleus (XII) of the rat. Based on differences in bouton and vesicle size and shape, synaptic specializations and association with postsynaptic organelles, five types of terminals were identified in XII. In order of decreasing frequency they were: 1) S-boutons (spherical vesicles with an asymmetrical synapse); 2) F-boutons (flattened vesicles with a symmetrical synapse); 3) P-boutons (pleomorphic admixture of flattened and spherical vesicles with a symmetrical synapse); 4) C-boutons (pleomorphic vesicles with a subsynaptic cistern); and 5) T-boutons (spherical vesicles with an asymmetrical synapse and subsynaptic dense bodies). S-boutons were the predominant type found on dendrites, while boutons containing flattened vesicles were more prevalent on motoneuron somata. C-boutons were restricted exclusively to cell bodies and large dendrites, and T-boutons were seen primarily on smaller dendritic profiles. These results are, in general, comparable to those previously described in the ventral horn and cranial nerve motor nuclei in several species. However, differences were noted. Specifically, large M-boutons and axo-axonic synapses were not observed in the present study. The functional significance of these findings are discussed in relation to oro-lingual behaviour.

Animals↗
PubMed1984

The ultrastructure of two distinct neuron populations in the hypoglossal nucleus of the rat.

An ultrastructural study of the hypoglossal nucleus (XII) in the rat has revealed two distinct neuronal populations. Hypoglossal motoneurons comprised the largest population of neurons in XII and were identified following injection of horseradish (HRP) into the tongue. Motoneurons were large (25-50 mu), multipolar in shape and distributed throughout XII. The nucleus was large, round and centrally located, and the cytoplasm was characterized by dense lamellar arrays of rough endoplasmic reticulum. In contrast, a second population of small (10-18 mu), round to oval shaped neurons was found restricted to the ventral and dorsolateral regions of XII. The nucleus was markedly invaginated and eccentric, the cytoplasm scant and filled with free ribosomes, and the absence of lamellar arrays of rough endoplasmic reticulum was conspicuous. Neurons of this type were never found to contain HRP reaction product. These results demonstrate that the hypoglossal nucleus does not consist solely of motoneurons, but includes a distinctly separate, presumably non-motoneuronal pool. Arguments are presented in favor of this second neuron population being interneurons. The functional significance of these findings in relation to tongue control is discussed.

Animals↗
PubMed1980

Organization of the cerebellar tongue representation in the monkey.

The cerebellar nuclei of rhesus monkeys were stimulated electrically and evoked responses of the tongue recorded with force-displacement transducers and electromyographically. Stimulation of the dentate (DN) and fastigial (FN) nuclei produced different effects on the tongue musculature, the former evoking movements characterized by changes in both the lateral and anteroposterior (AP) dimensions of the tongue and the latter movements associated with a preferential change in the AP dimension. While all three deep nuclei influenced the genioglossus muscle, the influences varied across nuclei in the following manner: FN produced the largest amplitude genioglossus mediated AP excusions and DN the smallest, with the nucleus interpositus (NI) occupying an intermediate position; and, FN and medial NI stimulation evoked changes in genioglossus respiratory activity whereas DN stimulation did not. These data indicate that the cerebellar tongue representation is organized into different functional zones and that within an anatomically broad representation of a single target muscle, nuclear functional specificity exists.

Animals↗