PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Pons”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 19 recordsLinked to original sources
PubMed1975

[Nuclei of the medulla oblongata and pons in the red deer and roe. III. Nuclei of the pons and tegmentum pontis].

The material for the studies was obtained from fragments of the brain stem, including the pons Varoli, of 2- and 6-year old red deer and of 2- and 3-year old female roe. The fixed material was mounted in paraffin and cut transversely into 15 micron sections, of which every fifth was examined. Preparations of the alcohol-fixed brain of one red deer and one roe were stained with methylene blue according to Nissl's modified method. Sections of the formalin-fixed brain of the other red deer and roe were stained according to the method of Klüver-Barrera with 0.1% solution of Luxor Fast Blue. Part III describes the structure and localization of the nerve nuclei of the portion of the brain stem under consideration. The following nuclei in the pons Varoli of the red deer and roe were described: nucl. medianus pontis, nucl. paramedianus pontis, nucl. ventralis pontis, nucl. lateralis pontis, nucl. dorso-lateralis pontis, nucl. peduncularis pontis. The nuclei, and especially in the central portion of the pons Varoli, are well developed in the species under discussion. With regard to the tegmentum pontis of the red deer and roe, a description of the structure and topography of the following nuclei is given: nucl. dorsalis tegmenti pontis, nucl. latero-dorsalis tegmenti pontis, nucl. dorsalis raphe, nucl. loci coerulei, nucl. reticularis dorsalis tegmenti pontis, nucl. reticularis ventro-lateralis tegmenti pontis, and nucl. reticularis ventro-medialis tegmenti pontis. The structure and localization of the nuclei of the tegmentum pontis are similar in both species, but the two first nuclei are much better developed in the roe than in the deer. The nucleus loci coeruliei could not be found in the roe.

Animals↗
PubMed1976

[Strychnine-neuronographic study of orbital cortex projections to structures of the pons varolii].

In adult cats, it was shown that the orbital cortex had direct contra - and ipsilateral projections to oral and caudal reticular nuclei of the pons, to caudal part of the Guden neuclei, to pons covering nucleus, to sulure nucleus, to trigeminal nuclei, and to such conducting formations, as the trapezoid body and pyramidal tract. The orbital gyri connections were mostly ipsilateral and to the caudal part of caudal reticular nucleus of the pons, to oral part of the reticular giganto-cellular nucleus, and to the own pons nuclei. The highest firing rate and amplitude were recorded in the inhibition zone of the reticular formation (the site of overlapping of the oral and caudal reticular nuclei of the pons).

Animals↗
PubMedDate not supplied

Afferent projections to the self-stimulation regions of the dorsal pons, including the locus coeruleus, in the rat as demonstrated by the horseradish peroxidase technique.

Afferent projections to the dorsal pons of the rat have been studied using the horseradish peroxidase (HRP) technique. HRP injections were made in each of the following regions: the vicinity of the locus coeruleus (LC); the periventricular gray, medial to the LC; the medial parabrachial region, lateral to the LC; the ventral cerebellum, dorsal to the LC; and the pontine reticular formation, ventral to the LC. Because intracranial self-stimulation (ICSS) has been obtained in these regions, the afferents have been discussed in terms of their possible contributions to the behavior. Previous ICSS studies of the dorsal pons have focussed on the LC as playing a central role. Presently identified inputs to the LC include: the dorsal raphe nucleus: the ventrolateral periaqueductal gray: the pontine reticular formation: the areas that contain the pontine and medullary noradrenergic and adrenergic cell groups: the lateral hypothalamic area: the contralateral LC: the deep cerebellar nuclei: the ventrolateral and parafascicular thalamic nuclei: and the parabrachial regions of the pons and midbrain.

Afferent Pathways↗
PubMed1978

Histochemical mapping of acetylcholinesterase and butyrylcholinesterase in the medulla oblongata and pons of squirrel (Funambulus palmarum).

The distribution of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) has been investigated in a series of sections passing through the medulla oblongata and pons of the squirrel brain. A comparison of the two enzymes has given an interesting picture of their selective localization in the different nuclei. Marked AChE activity has been observed in the cranial nerve nuclei. BChE activity in various nuclei of the medulla oblongata and pons is variable and occurs diffusely between the cells. Possible reasons pertaining to marked variation in AChE and BChE contents of various nuclei and fiber tracts have been discussed.

Acetylcholinesterase↗
PubMed1976

Inhibitory and facilitatory areas of the rostral pons mediating ACTH release in the cat.

To define the role of the rostral pons in the control of release of ACTH, we stimulated electrically (30 sec, 200 muA, 50 Hz) 128 sites in the dorsal rostral pons of 20 cats anesthetized with chloralose/urethane. Responses of arterial pressure to electrical stimulation were prevented by lesions placed previously in the medulla. Plasma concentrations of ACTH were measured by radioimmunoassay. Active areas consisted of three regions: 1) lateral inhibitory: Locus subcoeruleus and anteroventral locus coeruleus (mean deltaACTH: -189, -164, -145 pg/ml at 1.5,3.0 and 6.0 min respectively, P less than 0.01);2) intermediate facilitatory:principal locus coeruleus and lateral ventral tegmental nucleus (mean deltaACTH: +81, +68, +37 pg/ml; P less than 0.05); and 3) medial inhibitory: dorsal tegmental nucleus, dorsal raphé and medial ventral tegmental nucleus (mean deltaACTH; -211, -212, -115 pg/ml; P less than 0.01). The former two areas received direct projections from medullary neurons activated or inhibited by atrial stretch, and, in turn, give rise to adrenergic and cholinergic projections to the medial hypothalamus. Since the release of ACTH is inversely correlated with right atrial stretch, the results suggest that the lateral inhibitory area and the intermediate facilitatory area are involved in mediation of changes in release of ACTH in response to hemodynamic changes.

Adrenocorticotropic Hormone↗
PubMed1992

[Changes of the 5-HT content in hippocampus, midbrain-pons, spinal cord and concentration of blood glucose after intraperitoneal injection of ACTH in rats].

Effects of ACTH on the content of 5-HT in the hippocampus, midbrain-pons, and spinal cord and the concentration of blood glucose in rats by spectrofluorometric assay and glucose oxidase method were studied. ACTH ip 10 IU.kg-1 or 20 IU.kg-1 significantly increased the content of 5-HT in the hippocampus, midbrain-pons and spinal cord and blood glucose level, both in a dose-dependent manner; para-chloroaphetamine, p-Cpa 4 mg icv markedly reduced the 5-HT in these brain regions and spinal cord and the blood glucose level (P less than 0.01); the level of 5-HT and blood glucose were not significantly altered after icv p-Cpa+ip ACTH; adrenalectomy+ip ACTH markedly increased the 5-HT content in the brain regions and spinal cord, but the blood glucose was decreased (P less than 0.01); and 5-HT was markedly decreased by sc alloxan tetrahydrate+ip ACTH, but blood glucose did not decrease (P greater than 0.05). Thus, ACTH may influence the blood glucose level through central nervous system 5-HT, and the change of 5-HT may be related to the insulin (secretion).

Adrenocorticotropic Hormone↗
PubMed1979

[Myelinolysis of the pons Varolli].

A case of myelinolysis of pons varolli which was diagnosed only after a microscopic examination of the brain is described. Certain morphological features of the focus in pons varolli were observed. It is assumed that in this observation the development of central pontine myelinosis was influenced by the abuse of alcohol as well as by exacerbation of pulmonary tuberculosis.

Alcoholism↗
PubMed1978

Spinal projection to the dorsolateral nucleus of the caudal basilar pons in the cat.

In the cat, a spinal projection to a restricted area of the basilar pontine grey has been revealed with use of anterograde degeneration technique (Fink-Heimer). The area was ipsilateral to the spinal lesion, restricted to the far caudal limit of the pons, and included the dorsal and the dorsolateral subdivisions of the pontine nuclei (PN). Comparisons following high cervical, midthoracic and upper lumbar spinal lesions did not reveal any somatotopic organization. Only a few spinopontine fibers had origins below segmental level L4. Lesions of various quadrants of the cord indicated that the spinopontine fibers ascended through the dorsolateral funiculus, and not through either the dorsal or the ventral funiculi. Comparison with the degeneration effects of cerebral cortical lesions showed that the spinal projection to the PN overlapped to some extent with the projection from the first sensorimotor and second somatosensory cortices. In the rat no comparable spinopontine projection was found. It is suggested that the spinopontine pathway might forward information to the cerebellum from visceral sensory receptors or perhaps from pools of spinal interneurons.

Animals↗
PubMed1975

An ependymoblastoma of the pons.

A case of ependymoblastoma of the pons in a child is reported, the first so far described in this location. The case adds further evidence for the acceptance of ependymoblastomas as a specific variety of primitive human glioma.

Autopsy↗
PubMed1977

Amino acid incorporation in medulla, pons, midbrain and cortex following spinal cord hemisection in the cebus monkey (Cebus apella).

The effects of spinal cord hemisection on protein labeling in the medulla, pons, midbrain, and cortex in the Cebus monkey were studied by measuring the uptake of [3H]lysine into the trichloroacetic acid (TCA) precipitable and non-precipitable fractions of brain. Animals were sacrificed 3, 6 or 13 days after hemisection. Two normal animals and a 3-day sham operate were utilized as controls. Differences included individual animals, operated vs. unoperated animals, brain areas, and variation of brain areas over all postoperative days. The overall trend in brain radioactivity over postoperative days indicates stress and non-stress related components of brain response to spinal injury. Left-right side differences (L greater than R) were noted in the uptake of [3H]lysine into specific areas of brain over postoperative time, including leg areas of motor cortex, occipital cortex, and superior colliculus. A biphasic action of leg sensory cortical areas over time was noted, where L greater than R for the first 6 postoperative days and R greater than L at day 13. The factors possibly mediating radiolabeled amino acid uptake into protein are discussed in relation to demonstrated anatomical and neurochemical regenerative processes.

Animals↗
PubMed1978

Properties of apneusis produced by reversible cold block of the rostral pons.

Reversible cold block of the rostral pons was used to compare properties of normal and apneustic respiration in anesthetized, vagotomized, artificially ventilated cats. During apneusis we observed high frequency oscillations (HFO) in phrenic nerve activity which were reduced in frequency compared with those during a normal inspiration. Apneusis produced by mid-pontine transection or punctate pneumotaxic center (PC) lesion produced similar HFO changes. The minimal intensity of superior laryngeal nerve electrical stimulation needed to terminate a breath was higher early in an apneusis than at the same time during a normal breath. Later in apneusis the intensity required became constant and was approximately the same as that needed to end a normal inspiration at its natural termination. With intact vagi lung inflation produced a greater prolongation of expiration during apneustic respiration than during normal respiration. Apneustic type activity was observed in both phrenic and vagal inspiratory motoneurons. We suggest that: (1) HFO are generated without the PC, but the PC elevates the oscillation frequency; and (2) apneusis may result in part from a delayed activation of the normal inspiratory off-switch mechanism.

Action Potentials↗
PubMed1975

Attack, eating, drinking, and gnawing elicited by electrical stimulation of rat mesencephalon and pons.

Eating, drinking, and gnawing were electrically elicited from the rat mesencephalon in the vicinity of the lateral branch of the descending medial forebrain bundle, but attack was evoked from the dorsomedial tegmentum adjacent to the central gray. The effective zones continued further caudally to the dorsal posterior pons. Unlike hypothalamically elicited behavior, eating, drinking, and gnawing often persisted 5-40 sec after termination of stimulation. Vocalization and escape activity were obtained principally from the vicinity of central pain pathways originating from the anterolateral cord. Other electrodes produced eating, drinking, gnawing, and grooming, which began only after termination of stimulation.

Aggression↗
PubMed1976

Motivated behaviors elicited from hypothalamus, midbrain, and pons of the guinea pig (Cavia porcellus).

Eating, drinking, biting attack, male mating behavior, and gnawing were elicited by electrical stimulation through electrodes located predominantly in a region extending from the preoptic area through the lateral hypothalamus into the ventral midbrain. Escape and digging were elicited from a parallel but more medial region that overlapped the lateral zone only in the preoptic-anterior hypothalamic area. Several differentiable vocalizations were produced from sites distributed through most, although not all, areas explored. Sites yielding painlike responses were located principally in the vicinity of the presumed pain pathway traced after anterolateral cordotomy in other species. Reward was obtained from widespread sites that were generally congruent with catecholaminergic systems as described in the rat. Although there was considerable overlap of the effective zones for many responses, their underlying mechanisms were differentiated anatomically by localized differences in their distribution or functionally by the elicitation of pure responses from some electrodes. Response mechanisms localized in the brain stem of the guinea pig generally resembled those in the rat, although there were differences in details, especially in the posterior midbrain and pons.

Aggression↗
PubMed1978

Parabrachial pons mediates hypothalamically induced renal vasoconstriction.

The role of the parabrachial region of the dorsal rostral pons (PB) in mediating control of renal blood flow and of systemic arterial blood pressure was investigated in nine cats anesthetized with chloralose-urethan. Electrical stimulation through electrodes placed stereotaxically in lateral and medial positions in the hypothalamus (LH and MH) in PB and in ventrolateral reticular formation (VLRF) of each cat elicited pronounced systemic arterial pressor responses and renal vasoconstrictions. Stimulation parameters were adjusted so that renal flow responses elicited from each site were equal. Following a unilateral lesion in the PB, responses of renal vasoconstriction induced by hypothalamic stimulation were attenuated, but responses of arterial pressure were not altered. Stimulation of the VLRF, posterior to the lesion, consistently produced undiminished systemic pressor responses and renal vasoconstriction throughout the durations of the experiments excluding decay of renal vascular responsiveness. Thus, the data suggest that pathways mediating renal vasoconstriction in response to hypothalamic stimulation was discrete and pass through the parabrachial region, whereas pathways mediating systemic vasoconstriction in response to hypothalamic stimulation are distinct or less compact.

Animals↗
PubMed1975

Vascular malformations of the pons in children.

Three children reported here and an additional five patients from the literature with angiomas of the pons had a total of 19 clinical episodes of neurologic "illness." Thirteen of these episodes were ictal and six were progressive in onset. The progressive onset was identical with that occurring in patients with tumors of the brain stem. Laboratory and radiographic studies were not uniformly helpful in differentiating this disorder from the more common brain-stem glioma. The survival of these patients varies from several hours to 15 years.

Adolescent↗
PubMed1975

[The effect of training regimes on the vascular bed of the rabbit medulla, pons and midbrain].

The aim of the work was: 1) comparison of training results on two schedules of rotation and 2) establishment of the maximum period when the positive effect of the training was kept. The work was performed in 46 rabbits (42 of them were taken in experiments). All stresses were made in an electrocentrifuge with a 1 m radius. The blood vessels of the medulla oblongata, pons and midbrain studied by methods of injection and clearing of horizontal sections (120 mu) were taken as morphological control. It was shown that morphological control considerably confirms the picture of training of the organism to stresses. Schedule N2 (18 rotations without a preliminary limbering-up) proved to be more effective. The trained state of rabbits obtained in the process of training by this schedule retains for 3 weeks.

Animals↗