(n.) The middle segment of the brain; the midbrain. Sometimes abbreviated to mesen. See Brain.
Example Sentences:
(1) 5-HT containing terminals and fibers also were observed in the mesencephalon and appeared to run rostrally in the medial part of the medial forebrain bundle.
(2) Effects of noxious electrical tooth stimulations and intraarterial administration of bradykinin or inhalation of volatile anesthetics on substance P content in the diencephalon-mesencephalon, pons-medulla and the spinal cord were examined in the rat.
(3) In order to study the interactions between serotonergic mechanism and electrical stimulation of the mesencephalic central gray substance, rats were trained to lever-press for terminating aversive electric stimuli applied at the Periaqueductal gray and adjoining tectum of the mesencephalon.
(4) The activity of glycerophosphorylcholine phosphodiesterases was determined in the mesencephalon, diencephalon, cerebral hemispheres, cerebellum and olfactory bulb during postnatal development from P5 to P70 of rat brain.
(5) In addition, these amines caused a concurrent change in the release of ACh at perfusion loci in both thalamus and mesencephalon.
(6) Levels of acetylcholine were significantly elevated in the telencephalon and diencephalon + mesencephalon of rats killed by near-freezing during conditioned suppression of food-reinforced lever pressing, whereas levels of serotonin, dopamine, and norepinephrine were not altered.
(7) The onset of convulsions induced by these convulsants coincides with the fall in GABA content and GAD activity in the mesencephalon area, and in contrast, the cessation of the convulsions by PN supplement coincides with the recovery in both the parameters.
(8) However, a later component of the Cnf-AEP whose generation locus within the mesencephalon is unknown was modulated by bf stimulation.
(9) Six hours after treatment with AOAA the GABA levels in the cerebellum, the cortex, the ventral mesencephalon and the striatum.
(10) Responses of substantia nigra zona compacta neurons to nomifensine and amantadine were studied with intracellular recording techniques (current and voltage clamp) in in vitro slice preparation of rat mesencephalon.
(11) These results describe a novel neurochemical system within the rat basal ganglia that is regulated by dopaminergic innervation from the mesencephalon.
(12) The left vertebral angiography revealed an anteriovenous malformation in the mesencephalon mainly feeded by the thalamoperforate artery and the medial branch of the posterior choroidal artery.
(13) (1) In 27 animals microinjection of 25--100 ng of angiotensin II through chronic cannulae implanted in the preoptic region initiated drinking and in subsequent acute experiments influenced the spontaneous discharge rate of single neurons in the ipsi-lateral mesencephalon.
(14) Into the second week of embryo growth (E7-E15), GABA appears in the mesencephalon (E7) and the eye (E9-E10).
(15) Behavioral augmentation also has been shown with opioids such as morphine, and it is known that a stimulant action on dopaminergic perikarya in the ventromedial mesencephalon is critical to the development of behavioral sensitization to morphine.
(16) Since EKC- and NANM-induced cardiovascular and respiratory depression were not observed in conscious intact or chronic spinal dog, it is suggested that: 1) kappaergic system rostral to mesencephalon may play a role in counteracting these depressant effects of EKC; 2) sigma receptor-mediated tachypnea and tachycardia are dissociable; the tachypneic effect may be mediated through higher center while the medulla oblongata is involved in producing tachycardia.
(17) Critical points of changing axial orientation were identified at the mesencephalon, the Rathke pouch and third branchial arch, and with the hepato-cardio-respiratory complex split between the 2 axes.
(18) The local cerebral blood flow and oxygen tension in the brain cortex, the reticular formation of the mesencephalon and the posterior hypothalamus were studied in chronic experiments in non-anesthetized rabbits with experimentally induced myocardial infarction.
(19) The variation was in the order leptomeninges greater than hypothalamus greater than cerebral cortex = mesencephalon greater than cerebellum = brain stem.
(20) In the present work, using the indirect peroxidase-labelled antibody technique, we made a comparative study about the distribution of Met-enkephalin-like-immunoreactive (ELI)-cell bodies in rat mesencephalon; comparing animals that received colchicine into the lateral ventricle and animals that got the colchicine injected into different cerebral nuclei.
Tegmentum
Definition:
(n.) A covering; -- applied especially to the bundles of longitudinal fibers in the upper part of the crura of the cerebrum.
Example Sentences:
(1) The effects of quinpirole and sulpiride on dopamine (DA), dihydroxyphenylacetic acid (DOPAC) and accumulation of dihydroxyphenylalanine (DOPA) after inhibition of DOPA decarboxylase were determined for the striatum and tegmentum of 11- and 17-day-old rat pups.
(2) A low-intensity thermally evoked tail avoidance reflex (LITETAR) was used to study changes in nociceptive response produced by local anesthetics and cobalt chloride microinjected into the dorsal posterior mesencephalic tegmentum (DPMT) of conscious rats.
(3) The neighbouring neocortical areas receive afferents neither from the mediodorsal nucleus of the thalamus nor from the ventral mesencephalic tegmentum; their catecholamine innervation is mainly confined to the superficial layers and appears to be of noradrenergic nature.
(4) One infant had a unilateral infarction in the medulla and another showed extensive gliosis in the brainstem tegmentum along with a large infarction in the region of the anterior cerebral artery.
(5) Striking similarities were found between the functional pathways affected differentially by RET stimulation and well-defined cholinergic pathways which originate in the midbrain tegmentum.
(6) Single neurons in the midbrain tegmentum of rats showed clear discriminatory responses to three tones announcing either food or water or no reinforcement.
(7) ruber, anterodorsolateral midbrain tegmentum, superior and inferior colliculi, pontine gray, cerebral peduncles, medial pontine reticular formation, raphe and vestibular nuclei did not affect the acoustic structure of the calls tested.
(8) Fewer, but still ample numbers, of SP-reactive axons are present also in the ventral tegmental and retrorubral areas of the midbrain tegmentum and in the ventral pallidum of the basal forebrain, but only sparse ME-reactive axons are present in these areas.
(9) In lampreys, the majority of HRP-labeled cells were located along the length of the brainstem reticular formation in the inferior, middle, and superior reticular nuclei of the medulla, mesencephalic tegmentum, and nucleus of the medial longitudinal fasciculus.
(10) Both hyperphagic and hyperdipsic animals had significantly lower concentrations of 5-HT in forebrain than rats which sustained similar cuts in the tegmentum which did not affect ingestive behavior.
(11) The topographical distribution of neuropeptide-containing cell bodies, fibers and terminals was studied in human parabrachial nuclei and the pontine tegmentum with immunohistochemical stainings.
(12) These results indicate that bilateral lesioning of the mesencephalic lateral tegmentum, which disrupts the milk-ejection response, could damage somatosensory projections originating from the dorsal horn of the spinal cord, the lateral cervical nucleus, the dorsal column nuclei and the sensory and spinal trigeminal nuclei.
(13) In bullfrogs, AVT concentrations were greater in males, compared to females, in the amygdala pars lateralis, optic tectum, and tegmentum.
(14) By means of an extracellular glass microelectrode method, unitary discharges synchronized with the grouping discharges in the pelvic vesical branch with a rhythm of 2.2-2.5 Hz were recorded from the pontine micturition center in the dorsolateral pontine tegmentum.
(15) Areas rich in [3H]-SP binding were located in the ventral telencephalon, in the entire hypothalamic and thalamic region, in the midbrain tegmentum, in the optic tectum, in the valvulla cerebelli and in the medulla oblongata.
(16) WGA-immunoreactive (-ir) neurons were identified in the DRN, PAG and lateral dorsal tegmentum (LDTg) after PF and CM injections.
(17) Smaller numbers of double-labeled neurons were located in the B9 cell group and the region of the lateral midbrain tegmentum.
(18) Degenerating fibers were observed to descend bilaterally through the midbrain, pontine, and medullary tegmentum to the vicinity of the principal sensory and motor nuclei of the trigeminal nerve.
(19) Using a retrograde tracer technique with horseradish peroxidase, we have identified the afferent connections to the visual cortex from the dorsolateral pontine tegmentum (locus coeruleus, nucleus parabrachialis medialis and nucleus parabrachialis lateralis) as well as from the dorsal raphe nucleus.
(20) Descending projections through the caudal dorsolateral pontine tegmentum and into the medial medullary reticular formation may be involved in the initiation of sensorimotor inhibition.