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PubMed1979

Projections of precentral and premotor cortex to the red nucleus and other midbrain areas in Macaca fascicularis.

Midbrain projections from the precentral and premotor cortex were studied autoradiographyically in seven macaques. Earlier findings of Kuypers and Lawrence (1967) based on silver impregnated axonal degeneration were largely confirmed and partly extended. Laminar projections into the parvocellular red nucleus were found bilaterally from the somatotopic representation areas of the precentral cortex and three main divisions of premotor cortex (ventral, dorsal, and medial). The heaviest contralateral projection was recorded from the medial hemispheric aspects of area 6 (partly identical with the supplementary motor cortex). Homolateral projections were found from the limb areas of the precentral motor cortex to the magnocellular portion of the red nucleus and direct evidence for the overlap between corticorubral projections and corresponding areas of origin of the rubrospinal tract was obtained. Other projections concerned N. Darkschewitsch, N. Edinger-Westphal, suprarubral and dorsal mesencephalic reticular formation and adjacent lateral periaqueductal grey, substantia nigra, pretectal region, superior colliculus and N. tegmenti pedunculo-pontinus.

Animals↗
PubMed1995

Possible involvement of nitric oxide in red nucleus stimulation-induced analgesia in the rat.

There is considerable evidence that nitric oxide (NO) plays a role in synaptic transmission in both central and peripheral nervous systems. Recent studies have suggested the involvement of the L-arginine-NO pathway in nociceptive transmission/modulation. Electrical stimulation of the red nucleus in the rat evokes potent analgesia. Microinjection of different concentrations of L-arginine (1 nmol-1 mumol), but not of D-arginine, produced quick and long-lasting analgesia. Pretreatment with N-nitro-L-arginine methyl ester (1 mumol), a nitric oxide synthase inhibitor, significantly prevented L-arginine-induced analgesia. Further, pretreatment of animals with methylene blue, a known guanylate cyclase inhibitor, also attenuated the development of analgesia. Our results suggest that L-arginine caused production of NO, which in turn activated the red nucleus analgesic system.

Analgesia↗
PubMed1994

Expression of choline acetyltransferase immunoreactivity in the rat red nucleus after postnatal enucleation.

The presence of cholinergic neurones in the rat red nucleus (RN) is a controversial subject. We investigated this issue by immunocytochemistry in both adult, normal and neonatally enucleated rats. Choline acetyltransferase (ChAT)-immunoreactive neurones were found in the RN only of enucleated rats. An increase in cytochrome oxidase staining was also observed in the RN of enucleated rats. Our data support the concept that neurones in the rat RN are cholinergic and suggest that their activity could be modulated by the visual input.

Animals↗
PubMed1991

[The analgesic effect of red nucleus and strengthening effect thereof to the acupuncture analgesia].

The modulation of red nucleus (RN) to pain sense was researched with the latent period of radiant-heat tail flick of rats as standard of the pain threshold. The pain threshold of tail flick reflex was raised significantly by bilateral injection of glutamic acid into RN. Simultaneous injecting glutamic acid into RN and lidocaine into nucleus raphe magnus (NRM) could attenuate the raising effect of pain threshold of RN. This showed that the activated RN has analgesic effect and the NRM plays an important role in the descending inhibitory pathway of RN. The discharges of neurons in caudal part of nucleus spinalis tract nervi trigemini (cNST) evoked by stimulating nerve alveolaris inferior (nAI) with strong pulse were recorded with microelectrode. The nAI-evoked discharges might be inhibited by stimulating contralateral or ipsilateral RN. The RN inhibitory time course on nAI-evoked discharges were shortened after injecting lidocaine into NRM. This demonstrated that the inhibitory effect of RN on neurons in cNST is mediated by NRM. The electrical stimulation of acupoint "Jiache" could inhibit the pain-evoked discharges of neurons in cNST. The inhibitory time course of electrical acupuncture were prolonged by stimulating RN. This result revealed that the activated RN can strengthen the analgesic effect of acupuncture.

Acupuncture Analgesia↗
PubMed1975

Electrophysiological study of formation of new synapses and collateral sprouting in red nucleus neurons after partial denervation.

Intracellular recording was made from cat's red nucleus after chronic lesion of the nucleus interpositus (IP) of the cerebellum and the properties of the corticorubral EPSPs were examined. 2. It was found that the time to peak of the corticorubral ESPSs induced from cerebral peduncle (CP EPSP) of chronic cats was much faster than that of normal cats. There was no simple decay following the rapid rise and early summit; instead there was another peak as if the slow normal CP EPSPs were superimposed on the fast ones. 3. By stimulating two loci, sensorimotor cortex and the cerebral peduncle, the conduction velocities of the fibers responsible for the newly appeared fast-rising component of the corticorubral EPSPs were measured. They were almost the same as those of normal corticorubral EPSPs.

Action Potentials↗
PubMed1976

[Reactions of red-nucleus neurons in the alert cat to cutaneous stimulation].

Responses of the red nucleus (RN) neurones to cutaneous stimulation were studied in unanaesthetized chronic cats by means of microelectrode technique. It was revealed that the reactions were predominantly excitatory and the RN neurons had larger receptive fields covering one half of the body or all the limbs of the animal. The somatotopic principle of the cutaneous representation in RN was shown. The destruction of the cerebellar nuclei and sensorimotor cortex caused the lowering of the background activity of the RN neurones, changed their responses to cutaneous stimulation, as well as the narrowing and redistribution of the peripheral receptive fields. With all the changes described, the somatotopic character of the cutaneous representation in RN as preserved, though a large majority of RN neurones (52,8%) did not show this somatotopic distribution. The cerebellum is the main collector in transferring the cutaneous impulsation to the RN. In awake cats there were predominantly involved spinocerebellar pathways, activated by the flexor reflex afferents. The participation of the sensorimotor cortex in the reaction under study is revealed by the phenomenon of sprouting of the corticorubral axon terminals from the dendritic portions to the neuronal somata of RN.

Animals↗
PubMed1975

Ultrastructure of axonal reaction in red nucleus of cat.

Described here are ultrastructural changes in neurons of feline red nucleus exhibiting axon reaction after unilateral rubropsinal tratotomy at the C-2 level and surviving 2 to 65 days. Ultrastructural alterations included neurofilamentous hyperplasia; proliferation of smooth ER; temporary disappearance of organized granular ER with partial substitution by haphazardly arranged, broad cisternal profiles; loss of rosette ribosomes and occurrence of single ribonucleoprotein granules or an intercisternal amorphous density; increased numbers of subsurface cisterns and allied structures, often disposed in stacks; vesiculation and vacuolation of Golgi cisternae; prevalence of autophagic bodies derived in part from Golgi complexes; probable mitochondrial hyperplasia and various qualitative changes in these organelles; an increase in lipofuscin. Dendritic changes paralleled those of perikarya save that proliferation of subsurface cisterns and autophagic bodies was absent. Abnormalities of myelinated axons and boutons occurred and may have originated from retrograde degeneration of cortical neurons induced by lateral funiculotomy. Some perikarya were devoid of axosomatic boutons. Ultrastructural changes varied with the length of postoperative survival and were, at least partly, reversible. Chromatolysis was detectable light microscopically before ultrastructural abnormality appeared. The bearing of transneuronal mechanisms on axon reaction of central neurons and the protective effect of section of axons beyond the site of origin of collaterals are discussed.

Animals↗
PubMed1996

Neural unit activity in the trigeminal complex with interpositus or red nucleus inactivation during classical eyeblink conditioning.

During classical conditioning, many neurons in the trigeminal complex of rabbits exhibit activity that is related to the conditioned stimulus (tone), the unconditioned stimulus (airpuff), or to the conditioned response (eyeblink). For these reasons the trigeminal complex has been hypothesized to be a brainstem locus for the neuronal plasticity associated with conditioning. In this experiment, the learning-related activity (unit activity associated with the conditioned response) in the trigeminal is abolished when either the red nucleus or interpositus nucleus of the cerebellum is temporarily inactivated by cooling, but the stimulus-evoked activity is unaffected by cooling. This study and previous results support the suggestion that the learning-related activity seen in the trigeminal is driven by the interpositus by way of the red nucleus.

Animals↗
PubMed1992

[The analgesic effect of red nucleus and preliminary research on its mechanism].

The spontaneous discharges of neurons in red nucleus (RN) of rats have been recorded with microelectrode. The discharge frequency of most RN neurons was changed by nociceptive electrical stimulation of nervi peronaeus communis or nervi tibialis or by nociceptive mechanical stimulation of tail or hind leg. The electrical activities of the somatic sensory neurons in the nucleus ventralis posterolateralis (VPL) of thalamus and of the visceral sensory neurons in the nucleus anterior and nucleus parafascicularis of thalamus have been recorded. According to the form of response to the peripheral nociceptive stimulation the neurons concerned could be divided into three types: pain-excited, pain-inhibited and pain-nonrelated. Electrical stimulating RN could change the spontaneous discharge frequency of somatic pain-related neurons of VPL and visceral pain-related neurons of nucleus anterior and nucleus parafascicularis, and could inhibit their response to somatic and visceral nociceptive stimulation respectively, but did not have influence on the activity of most pain-nonrelated neurons in VPL. The effects of electrical stimulating RN and microinjecting Ach into RN on the same pain-related neuron in VPL were similar. The experimental results show that RN can receive the somatic afferent impulses, that the excited RN can inhibit the transmission of somatic and visceral nociceptive impulses into the thalamus, and that the analgesic effect of RN is concerned with Ach.

Animals↗
PubMed2003

Role of GABA A and GABA B receptors in GABA-induced inhibition of rat red nucleus neurons.

We investigated GABA receptor subtypes mediating GABA-induced inhibition of red nucleus (RN) neuronal firing recorded extracellularly from anaesthetized rats. GABA response was mimicked by the GABA(A) agonists muscimol and isoguvacine in all cases and was partially blocked by the GABA(A) antagonist bicuculline. The GABA(B) agonist baclofen induced a long-lasting inhibition in 84% of cells. Neurons responding to either GABA(A) or GABA(B) agonists were equally distributed within the RN. The GABA(C) receptor agonist cis-amino-crotonic acid (CACA) did not modify RN neuronal firing; at high doses CACA occasionally induced inhibition abolished by bicuculline and thus mediated by GABA(A) receptors. We conclude that the inhibitory effects of GABA in the RN are mediated by both GABA(A) and GABA(B) receptors, whereas GABA(C) receptors are not involved.

Action Potentials↗
PubMed1994

Pharmacological characterisation of excitatory synaptic transmission in the cat red nucleus in vivo.

Extracellular recordings were made from the magnocellular neurones of the red nucleus (mRN) in anaesthetised cats. A study was made of the effects of selective excitatory amino acid receptor antagonists on excitatory monosynaptic responses evoked from the sensorimotor cortex (SMC) and cerebellar interpositus nucleus (IPN). Iontophoretically applied CNQX and NBQX antagonised both SMC and IPN responses whereas, D-AP5 inhibited the SMC response but was ineffective to the IPN. At currents that selectively antagonised NMDA responses, CPPene had no effect on either SMC or IPN responses. 7-chlorokynurenate inhibited both SMC and IPN responses but required currents that antagonised both AMPA and NMDA responses and was therefore acting in a non-selective manner. Iontophoretically applied glycine was inhibitory to both agonist and synaptic responses, whilst D-serine potentiated NMDA responses but did not enhance monosynaptic responses of the SMC. However in the presence of either 7-chlorokynurenate or high currents of CNQX that reduced the SMC synaptic activation of the mRN neurones, D-serine attenuated the inhibitory action of these antagonists. It is concluded that monosynaptic responses from the SMC are mediated by both NMDA and non-NMDA receptors whereas the monosynaptic responses evoked from the IPN are mediated only by non-NMDA receptors. The lack of effect of CPPene is consistent with the postulate that two NMDA receptor subtypes are present on mRN neurones.

Animals↗
PubMed2003

Histamine elicits neuronal excitatory response of red nucleus in the rat via H2 receptors in vitro.

Perfusing slices with histamine (1-100 microM) produced an excitatory response in rat rubral neurons (118/132, 89.4%). The histamine-induced excitation was not blocked by the low-Ca2+/high-Mg2+ medium (n=10), supporting a direct postsynaptic action of the amine. Histamine H2 receptor antagonist ranitidine effectively blocked the excitatory response of rubral neurons to histamine (n=26), but H1 receptor antagonist triprolidine did not (n=24). The excitatory effect of histamine could be mimicked by dimaprit, a highly selective H2 receptor agonist (n=24), and the dimaprit-elicited excitation of the rubral neurons could be blocked by ranitidine (n=16), but not by triprolidine (n=9). In addition, H1 receptor agonist 2-pyridylethylamine could not elicit any response in rubral neurons (n=12). These results indicate that histamine excites red nucleus neurons through H2 receptors and suggest that the histaminergic afferent fibers may play an important functional role in the sensorimotor integration through the red nucleus.

Animals↗
PubMed1997

Red nucleus inhibits breathing during hypoxia in neonates.

Conscious, anaesthetized and decerebrate young mammals respond to acute hypoxia with an initial increase in breathing followed by a fall to, or to below, pre-hypoxic levels--the biphasic ventilatory response. The ventilatory rise is due to sustained hypoxic stimulation of the peripheral chemoreceptors. We present evidence from brain stem and peripheral chemoreflex studies supporting the concept that, in addition to the peripheral chemoreceptors, hypoxia also activates brain stem pathways that inhibit ventilation. A key part of the inhibitory pathway is an area within the red nucleus. Destruction of this area in young decerebrate rabbits abolishes the ventilatory fall during hypoxia, yet has no effect on respiratory control during normoxia and does not affect arterial blood pressure changes in hypoxia. In support of this hypothesis, we report that there are neurones within the red nucleus that increase their discharge in hypoxia. The role of higher brain stem/hypothalamic function in central respiratory control during hypoxia in the fetus and neonate are considered.

Animals↗
PubMed2000

Biperiden hydrochlorate ameliorates dystonia of rats produced by microinjection of sigma ligands into the red nucleus.

It has been reported that the imbalance of anticholinergic and antidopaminergic activity of each neuroleptic drug correlates with the capacity to produce neuroleptic-induced acute dystonia (NAD) and the major focus of NAD is thought to be the striatum. Anticholinergic drugs are highly effective on NAD, but they are partially effective on neuroleptic-induced tardive dystonia and their effect on idiopathic dystonia is disappointing. Recently, it has been reported that the unilateral microinjection of sigma (sigma) ligands into the red nucleus induces torticollis of rats. This animal model appears to be a model of dystonia, but it is not clear whether it is suitable for NAD in man. To clarify this issue, we investigated the effect of an anticholinergic drug, biperiden hydrochlorate (BH), on this animal model. This study revealed that BH dose-dependently ameliorated dystonia of rats induced by two sigma ligands, whether each sigma ligand had dopaminergic affinity or not. This animal model of dystonia appears to be a model of NAD in man from the viewpoint of treatment-response. The results also suggest that not only dopaminergic and cholinergic systems but also sigma system, and not only the striatum but also the red nucleus, may play an important role in the pathophysiology of NAD.

Animals↗
PubMed1987

Limb specific connections of the cat magnocellular red nucleus.

Afferent and efferent connections of the limb specific divisions of the cat magnocellular red nucleus (RNm) were traced using the bidirectional transport of wheatgerm agglutinin-horseradish peroxidase complex (WGA-HRP). Injection sites within forelimb or hindlimb RNm regions were identified by microelectrode recording and confirmed by the position of labeled rubrospinal terminals. Additional injections into structures that project to, or receive input from, RNm confirmed the somatotopic organization of these pathways. The forelimb region of RNm receives input from the posteriolateral part of the anterior interpositus nucleus (NIA) and the intermediate part of the posterior interpositus nucleus (NIP). The hindlimb region of RNm receives input from anteriomedial NIA and medial NIP. Terminals of NIA cells densely fill all of RNm, but terminals of NIP cells form a half shell on the medial, ventral, and posterior borders of RNm without encroaching on RNm's lateral edge or central core. Forelimb and hindlimb RNm are reciprocally connected with the caudal cuneate and gracile nuclei respectively. There is little or no input to RNm from the medial or lateral cerebellar nuclei. Forelimb RNm, which also contains a face representation, projects to the lateral reticular nucleus, cell group f of the inferior vestibular nucleus, the facial nucleus, the main sensory nucleus of the trigeminal nerve, the caudal cuneate nucleus, the parvicellular reticular formation, and cervical segments of the spinal cord. A few fibers from forelimb RNm project directly to motor neurons in the lower cervical cord. Hindlimb RNm projects to only the lateral reticular nucleus, gracile nucleus, and lower spinal segments. Forelimb and hindlimb RNm project to different regions of the lateral reticular nucleus with some overlap.

Afferent Pathways↗
PubMed1983

Topographic changes in high-affinity glutamate uptake in the cat red nucleus, substantia nigra, thalamus, and caudate nucleus after lesions of sensorimotor cortical areas.

The distribution of presumed glutamatergic projections from sensorimotor cortical areas to the red nucleus (RN), the substantia nigra (SN), the ventrolateral thalamic complex, and the caudate nucleus (CN) was investigated in the cat. For this purpose, the changes in the sodium-dependent high-affinity glutamate uptake (HAGU) rate were measured in homogenates of tissue microdissected from various parts of these subcortical structures after chronic surgical ablation of sensorimotor cortical areas. After 8 to 10 days survival, significant reductions in HAGU activity were noted in the structures studied on the side ipsilateral to the operated cortex. Within each structure, various quantitative or qualitative changes were observed. Higher decreases in HAGU activity were found in the caudal part of the RN, the ventrolateral thalamic nucleus, and the dorsolateral part of the CN than in the other parts of these structures. The lateral part of the SN showed a large decrease in HAGU rate and its medial part a small but significant increase. Referring to the anatomic data concerning the organization of cortical projections from sensorimotor areas to the structures studied, it was shown that our results support the view that glutamate could act as a neurotransmitter along various corticosubcortical pathways.

Animals↗
PubMedDate not supplied

Synaptic plasticity in the red nucleus and learning.

Pairing of the stimulus to the cerebral peduncle (CP) with that to the forearm skin leads cats to flex their forearms within a 10-day training period in response to stimulus to CP, which was initially ineffective. Behavioral study and extracellular unit analysis suggested that the cellular mechanism for this conditioning lies at the corticorubral (CR) synapses. Since formation of new CR synapses occurs in parallel with the recovery from behavioral deficits after brain damage and peripheral nerve cross-innervation, we explored the possibility that the formation of new CR synapses underlies conditioning. We investigated the time course of the CR excitatory postsynaptic potentials (EPSPs) as well as the distribution of the CR synapses on the somadendritic membrane of the red nucleus neurons and compared them with those observed in control animals. In conditioned animals, the times-to-peak of the CR EPSPs were significantly shorter than those in control animals. Electron microscopic studies demonstrated that more CR synapses make contact with large, i.e. proximal, dendrites and somata of red nucleus neurons in conditioned cats than in control ones. These results support the view that the formation of new synapses on the proximal dendrites and soma underlies classical conditioning in the cat.

Animals↗