Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Efferent Pathways”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 829 records · Page 46Linked to original sources
PubMed1991

Production and survival of projection neurons in a forebrain vocal center of adult male canaries.

Neurons are produced in the adult canary telencephalon. Many of these cells are incorporated into the high vocal center (nucleus HVC), which participates in the control of learned song. In the present work, 3H-thymidine and fluorogold were employed to follow the differentiation and survival of HVC neurons born in adulthood. We found that many HVC neurons born in September grow long axons to the robust nucleus of the archistriatum (nucleus RA) and thus become part of the efferent pathway for song control. Many of these new neurons have already established their connections with RA by 30 d after their birth. By 240 d, 75-80% of the September-born HVC neurons project to RA. Most of these new projection neurons survive at least 8 months. The longevity of HVC neurons born in September suggests that these cells remain part of the vocal control circuit long enough to participate in the yearly renewal of the song repertoire.

Animals↗
PubMedDate not supplied

Autonomic variations after stellate ganglion block: are they evidence of an autonomic afference?

Sympathetic skin response and plethysomography were used to assess the sympatholytic effect of the stellate ganglion block with morphine and bupivacaine in patients affected by a sympathetic algodystrophy of the upper limb. Morphine did not show any analgesic or sympatholytic effect. The distribution of the sympatholytic effect and the clinical findings of pain relief without somatic sensory-motor impairments obtained with the local anaesthetic, support the presence of a blockade of the sympathetic efferent pathway as well as of an afferent contingent of fibres probably and mainly involved in sympathetic reflexes.

Afferent Pathways↗
PubMed1990

[Angiography findings before and following transplantation of free myocutaneous flaps].

Prerequisite for successful split-skin flap transplants of myocutaneous flaps is the presence of adequate adjacent afferent and efferent vessels, thus making an arteriography of the receiving region mandatory during surgery preparation. In 20 or 29 patients in whom a split myocutaneous flap was transplanted to the lower leg, angiography revealed 22 pathological or other therapyrelevant findings. Besides the afferent vessels it is basically necessary to visualise the peripheral efferent pathways in order to prevent that vascular anastomosis to the split-skin flap obstructs the blood supply of the leg.

Adolescent↗
PubMed1989

Hereditary ataxia.

The hereditary ataxias, also referred to as the spinocerebellar degenerations, comprise a series of clinical manifestations that include ataxia and dysmetria, resulting from the predominant involvement of the cerebellum and its afferent and efferent pathways. These disorders are system degenerations; many of them are specific entities clearly inherited as autosomal dominant or autosomal recessive traits. Although the clinical manifestations and neuropathologic findings of cerebellar disease dominate the spinocerebellar degenerations, there may also be characteristic changes in the basal ganglia, optic atrophy, retinitis pigmentosa, or peripheral nerve disease. There are many gradations from pure cerebellar manifestations to mixed cerebellar and brain-stem disorders, cerebellar and basal ganglia syndromes, and spinal syndromes or peripheral nerve disease. The clinical picture may be consistent in one family, but sometimes there is a characteristic syndrome in the majority of family members and an entirely different disorder in one or several members.

Chromosome Mapping↗
PubMed1989

[Organization of the direct projections of the Tsai ventral tegmental area to the hippocampus].

In this report we have examined the distribution in the ventral tegmental area of Tsai (VTA-A10) of the neurons projecting to the hippocampal formation (HF) by injecting, in different combinations, retrograde fluorescent tracers (Fast Blue, 2% and Nuclear Yellow, 1%) in several hippocampal areas. The distribution of the VTA labeled neurons suggest a topographic organization of the VTA efferent pathway towards the HF. These results are in agreement with the concept that precise topography of the projections is a distinctive feature of the dopaminergic systems in general.

Animals↗
PubMed1989

Evidence of muscarinic receptor subtypes in airway smooth muscle of normal volunteers and of chronic obstructive pulmonary disease patients.

Since there have been only a few studies on muscarinic receptor subtypes in airway smooth muscle, the effect was investigated of pirenzepine on airways of patients with chronic obstructive pulmonary disease (COPD) and the functional responses compared from these patients with those from healthy subjects. Our data demonstrated that the therapy with pirenzepine significantly improved ventilatory function in patients with COPD. The data also suggested that this drug exerts its action on small airways, but not larger airways in normal subjects. It is possible that in healthy human beings pirenzepine produces mild bronchodilation by means of a vagal efferent blockade, while in patients with COPD, it may be effective because it not only decreases the activity of the vagal efferent pathway, but also decreases the sensitivity of vagal sensory endings and causes a vagal afferent blockade.

Atropine↗
PubMed1977

Corticosteroids in the management of herpetic eye disease.

The discriminate use of topically applied corticosteroids to modify or abolish the inflammatory response in herpetic stromal keratitis, has, as its objectives, the prevention of visual loss from corneal scarring and disorganization and a lessening of the morbidity associated with this disese. Steroids may be expected to have a profound anti-inflammatory effect in antibody-complement mediated inflammation and are effective in delayed hypersensitivity as in homograft rejection. The equally profound effect of pharmacological vasoconstriction may enable steroids to impede both afferent and efferent pathways in an immunological reflex arc, and they may be expected to reduce inflammation of nonimmunogenic origin. The adverse effects of the misapplication of these potent drugs in herpetic keratitis, in terms of an increase in the rate of complications and in the severity and morbidity of the disease, should be emphasized again.

Administration, Topical↗
PubMed1987

[Reflex pressure response to the electric stimulation of different parts of the rat stomach].

The role of the autonomic nervous system in the pressor response to the electrical stimulation of different gastric zones has been studied in rats. The stimulus was applied before and after the following interventions: bilateral vagotomy, ganglionic blockade, alpha-adrenergic receptor blockade and beta-adrenergic receptor blockade. After the ganglionic blockade no pressor responses to the electrical stimulus were observed. After the alpha-adrenergic blockade a lower pressor response was observed. A hypertensive response can be induced by mechanical, chemical or electrical stimulation of gastric receptors. It is concluded that the pressor reflex following the application of an electrical stimulus on different zones of the digestive tract is mediated by the sympathetic nervous system and that the efferent pathways are mainly alpha-adrenergic ones.

Adrenergic alpha-Antagonists↗
PubMed1987

Reflex pressor response to gastric mechanical stimulation in rats.

Neural and humoral mechanisms involved in the reflex pressor response during mechanical stimulation of the stomach of rats were investigated. The arterial blood pressure response was prevented by inhibition of alpha-adrenergic vasoconstriction using either an alpha-adrenergic blocker or a ganglionic blocker. In addition, there was a small decrease in the response after nephrectomy. However, there were no alterations in the response after beta-adrenergic blockade, bilateral adrenalectomy, inhibition of converting enzyme activity with enalapril or bilateral cervical vagus nerve transection. The heart rate was not modified after either intervention. After vagotomy the time of recovery of the basal blood pressure was significantly prolonged. It can be concluded that the blood pressure response to mechanical stimulation of the stomach wall is of neural rather than of humoral origin and mainly involves activation of alpha-adrenergic receptors. Vagal efferent pathways could be also involved.

Adrenalectomy↗
PubMed1977

Idiopathic orthostatic hypotension and the Shy and Drager syndrome; Physiological studies in four cases; pathological report of one case.

Five cases of idiopathic orthostatic hypotension are presented. Physiological tests were performed in four cases which demonstrated that the lesion in the sympathetic system was most probably situated in the intermediolateral columns in three cases. In one case the lesion was localized on the efferent pathway either at the preganglionic or the postganglionic level. These four patients had also evidence of parasympathetic dysfunction. In the fifth case the clinical diagnosis of Shy and Drager syndrome was confirmed by pathological examination of the nervous system which revealed intermediolateral cell loss and the pathological findings commonly observed in the striato-nigral and olivo-ponto-cerebellar degenerations.

Aged↗
PubMed1988

The importance of baro- and chemoreflexes in the control of the fetal cardiovascular system.

The information gained about the afferent traffic from carotid arterial baro- and chemoreceptors by direct recordings made in the sheep fetus is reviewed. Less is known about aortic baro- and chemoreceptor discharge during this period, and virtually nothing is known about the discharge of other vagal mechano- or chemoreceptor afferents. Knowledge about the functional integrity of sympathetic and parasympathetic efferent pathways is reviewed. Then the various methods which have been used for assessing fetal baro- and chemoreflexes are discussed: the crucial problem here is that there are no techniques available for either increasing or decreasing the discharge of these receptors specifically. Because they have been widely used, however, and are of clinical importance, the effects upon the fetal circulation of hypoxia and asphyxia are reviewed specifically. The relative contributions of baro- and chemoreflexes in producing these effects are considered against the background of the plethora of other processes which operate under these conditions.

Animals↗
PubMed1988

Autonomic nervous system in haemodialysis.

Fifty-two patients with terminal chronic renal failure on haemodialysis were assessed for the existence of autonomic neuropathy using the Valsava index. The values in the patients were lower than in the controls. Only a few symptoms could be related to the autonomic neuropathy. No correlation was found between Valsalva index and orthostatic or intradialysis hypotension, motor-nerve conduction velocity or plasma intact parathyroid hormone. Having demonstrated the existence of autonomic neuropathy, eight healthy subjects and ten patients on haemodialysis were studied to locate the segment of the autonomic reflex are affected. Heart rate and intraarterial pressure were monitored during the following tests: phenylephrine; hyperventilation; cold pressor; atropine; tyramine and adrenaline. An alteration was observed in baroreceptors, together with adrenergic hyperexcitability (reflected in the hypersensitivity of the sympathetic efferent pathway) and a greater response to the stimulus for the release of extra-adrenal adrenaline. The lower response to atropine is indicative of vagal alteration.

Adolescent↗
PubMed1988

Dopamine-sensitive anticonvulsant site in the rat striatum.

The basal ganglia are involved in the organization of movement and function in the initiation and expression of generalized and limbic seizures. Dopamine is the principal neurotransmitter of the mesencephalic efferent pathways terminating in the mammalian striatum. No function has been ascribed to mesostriatal dopamine in the control of seizure spread in the brain. This work presents evidence that bilateral application of picomole amounts of apomorphine (a dopamine agonist) into the striatum confers protection against seizures produced by pilocarpine (a cholinergic agonist) in rats. The anticonvulsant effect of apomorphine is topographically confined to the caudate-putamen, nucleus accumbens, and olfactory tubercle. Bilateral application of nanomolar amounts of haloperidol (a dopamine antagonist) into the caudate-putamen or systemic application of haloperidol both lower the threshold for pilocarpine-induced seizures. Local application of an excitatory amino acid N-methyl-D-aspartate, into the substantia nigra pars compacta, ventral tegmental area, or retrorubral area, sites of origin of mesostriatal dopaminergic pathways, protects rats against seizures produced by pilocarpine. These results suggest that dopaminergic transmission in the striatum may be operative in complex neuronal networks modulating the seizure threshold.

Amino Acids↗
PubMed1988

Three-dimensional pattern of enkephalin-like immunoreactivity in the caudate nucleus of the cat.

Recent anatomical investigations of the mammalian neostriatum have uncovered discrete neurochemical zones characterized by low levels of AChE and high levels of enkephalin-like immunoreactivity (ELI) compared with the surrounding neostriatal tissue. These regions, termed striosomes, which appear as patches in individual sections, have been associated with specific afferent and efferent pathways that differ from those of the surrounding neostriatal tissue. In the present study, the 3-dimensional distribution of these enkephalin-rich compartments in the caudate nucleus of the adult cat was investigated using computer-assisted 3-dimensional reconstruction techniques. Series consisting of coronal, sagittal, and horizontal tissue sections were obtained. In individual sections, discrete patches of intense enkephalin-like immunoreactivity appeared against a lighter-staining background. Three-dimensional reconstructions revealed that these patches overlapped across sections to form a highly inter-connected structure within the head and body of the caudate nucleus. Several structural features were evident in these reconstructions that appeared to be similar across animals. One consistent pattern was the formation of enkephalin-labeled finger-like structures radiating from the ventricular edge diagonally across the width of the nucleus. Smaller crossbridges were seen connecting the fingers, which often resulted in the formation of claws or rings of enkephalin-like immunoreactivity. These elements appear to align across planes to form a lattice-like structure outlining continuous regions of matrix. This structure may provide a basis for the orderly interaction between the patch and matrix compartments.

Animals↗
PubMed1986

[Sensory and motor effects of thalamic stimulation in man. Clinical applications].

Human thalamus exploration was performed using stereotactic electrodes in ranks of two millimetres following three trajectories at two millimetres' intervals in the same sagittal plane. Stimuli were applied alternately with tracing recordings. Characteristics of the various thalamic systems were defined under normal and pathological (deafferentation of thalamus, dyskinesia) conditions. Therapeutic applications of this topographical analysis of thalamus are discussed.

Afferent Pathways↗