Direct cortical projections to the parabrachial nucleus in the cat

Direct projections from the cerebral cortex to the parabrachial nucleus in the cat were examined by the horseradish peroxidase (HRP)method. When HRP was injected into the parabrachial nucleus, retrogradely labeled neuronal cell bodies were seen, bilaterally with an ipsilateral predominance, mainly in the orbital gyrus, the lateral bank of the presylvian sulcus, and a restricted region in the infralimbic cortex on the medial surface of the frontal lobe (stereotaxic coordinates; Fr: 22, L: 1, H: -1); all labeled neurons were in deep pyramidal cell layer. After injecting HRP conjugated to wheat germ agglutinin (WGA-HRP) into the cortical regions where retrogradely labeled neurons were found after injecting HRP into the parabrachial nucleus, anterogradely labeled cortical fibers were traced to the parabrachial nucleus. Corticoparabrachial fibers originating from the orbital gyrus and the lateral bank of the presylvian sulcus ran ipsilaterally through the internal capsule and the cerebral peduncle down to the lower brainstem, whereas those from the infralimbic cortex coursed down ipsilaterally through the medial forebrain bundle. These cortical fibers to the parabrachial nucleus were distributed bilaterally with an ipsilateral predominance. Cortical fiber terminals in the parabrachial nucleus were topographically arranged: Corticoparabrachial fibers from the lateral bank of the presylvian sulcus ended most massively in the dorsal part of the lateral parabrachial nucleus. Corticoparabrachial fibers from the orbital gyrus ended most heavily in the medial parabrachial nucleus and less heavily in the lateral parabrachial nucleus. Corticoparabrachial fibers from the infralimbic cortex ended mostly in the parabrachial regions surrounding the brachium conjunctivum.

An anterograde-retrograde transneuronal transport of conjugates of wheat germ agglutinin with horseradish peroxidase (WGA-HRP): labeling of neurons in the reticular nucleus of the thalamus with WGA-HRP injected into the posterior column nuclei in the cat

Neuronal cell bodies in the reticular thalamic nucleus (R) were labeled with wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) which was injected contralaterally into the posterior column nuclei (PCN) in the cat. The tracer was assumed to be transported to the posterolateral ventral thalamic nucleus (VPL), where it could escape from axon terminals of the PCN neurons and then be taken up by axon terminals of R neurons to label retrogradely the cell bodies of the R neurons.

Distribution of premotor neurons for the hypoglossal nucleus in the cat

After injecting horseradish peroxidase into the hypoglossal nucleus, labeled neuronal cell bodies were constantly seen bilaterally with a slight ipsilateral dominance in the parvocellular reticular formation and reticular regions around the hypoglossal nucleus, ipsilaterally in the nucleus of Kölliker-Fuse, and contralaterally within the hypoglossal nucleus. A few labeled neurons were often found bilaterally with an ipsilateral dominance in the inter- and supratrigeminal regions around the motor trigeminal nucleus, parabrachial nucleus, ventral portions of the medial reticular formation of the pons and medulla oblongata, and dorsal tegmental regions and central gray of the midbrain.

Distribution of premotor neurons for orbicularis oculi motoneurons in the cat, with particular reference to possible pathways for blink reflex

After injecting horseradish peroxidase into the facial nucleus regions containing orbicularis oculi motoneurons, labeled neuronal cell bodies were found in the lateral medullary reticular formation, pretectal olivary nucleus, sensory trigeminal nuclei, lateral and medial parabrachial nuclei, ventromedial reticular formation medial to the facial nucleus, red nucleus and its surroundings, anterior horn of the upper cervical cord, medullary raphe nuclei, oculomotor nucleus and its surroundings, nuclei of Darkschewitsch, Cajal and Edinger-Westphal, ventral part of the midbrain central gray, pontine tegmentum, lateral vestibular nucleus and deep layers of the superior colliculus.

Trigeminal primary afferent neurons projecting directly to the solitary nucleus in the cat: a transganglionic and retrograde horseradish peroxidase study

After applying horseradish peroxidase to peripheral branches of the trigeminal nerve in the cat, the lingual and pterygopalatine nerves were found to contain fibers which ended ipsilaterally in the rostral portions of the solitary nucleus (SN); massively in the medial and ventrolateral SN, moderately in the intermediate and interstitial SN and sparsely in the ventral SN. The rostralmost part of the SN was free from labeled terminals. After injecting the enzyme into the SN portions rostral to the area postrema, small neurons were scattered in the maxillary and mandibular divisions of the trigeminal ganglion.

Direct projections from the substantia nigra to the posterior thalamic regions in the cat

The substantia nigra (SN) of the cat was shown, by the anterograde and retrograde horseradish peroxidase methods, to contain neurons which send their axons to the caudomedial portions of the suprageniculate nucleus and/or lateroposterior nucleus of the thalamus; these neurons were located in the restricted region in the lateral part of the SN, which corresponds to the pars lateralis of the SN.

Projections from the parvocellular part of the posteromedial ventral nucleus of the thalamus to the lateral amygdaloid nucleus in the cat

It was shown in the cat by anterograde and retrograde WGA-HRP methods that the medial portion of the parvocellular part of the posteromedial ventral nucleus of the thalamus (VPMpc-m) sent fibers ipsilaterally to the rostrodorsal part of the lateral amygdaloid nucleus (Al-rd). The regions of the orbital gyrus (OG), which were connected reciprocally with the VPMpc-m, were also observed to send fibers to the Al-rd. Thus the VPMpc-m was assumed to project to the Al-rd directly, and indirectly via the OG.

The posteromedial ventral nucleus of the thalamus (VPM) of the cat: direct ascending projections to the cytoarchitectonic subdivisions

The posteromedial ventral nucleus (VPM) of the cat is divided cytoarchitectonically into the magnocellular (VPMmc), lateral parvocellular (VPMpcl), and medial parvocellular (VPMpcm) divisions. Cell bodies of neurons in the VPMpcm are small, while those in the VPMpcl are small to medium-sized. The VPMmc contains large neurons. Direct projections from the lower brain stem structures to each of the three divisions of the VPM were examined by the retrograde horseradish peroxidase (HRP) method. When HRP injection was done into the VPMmc, labeled neurons were mainly located contralaterally in the ventral division of the principal sensory trigeminal nucleus (Vp), in the rostral part of the oral subnucleus in the spinal trigeminal nucleus (Vsp), and in the interpolar subnucleus of the Vsp; a few labeled neurons were also found contralaterally in lamina I of the caudal subnucleus of the Vsp. When HRP injection was restricted to the VPMpcl or VPMpcm, HRP-labeled neurons were mainly observed ipsilaterally, respectively, in the dorsal division of the Vp, or in the parabrachial nucleus (PBN) regions dorsomedial and ventromedial to the brachium conjunctivum. After HRP injection into the parvocellular part of the VPM (VPMpc), labeled neurons were also seen contralaterally in the Vsp, but these were far less numerous than those seen after HRP injections into the VPMmc. Thus, each of the three divisions of the VPM receives main ascending afferent fibers from different brain stem structures; the VPMpcm, VPMpcl, or VPMmc receives afferent fibers, respectively, from the PBN ipsilaterally, from the dorsal division of Vp ipsilaterally, or from the ventral division of the Vp and the Vsp contralaterally.

A pretectofacial projection in the cat: a possible link in the visually-triggered blink reflex pathways

A direct projection from the pretectum to the facial motor nucleus was shown to exist in the cat by the anterograde and retrograde horseradish peroxidase (HRP) methods. Pretectofacial fibers arise from the olivary pretectal nucleus and end mainly in the dorsal division of the facial motor nucleus, bilaterally, with a contralateral predominance. It is known that the olivary pretectal nucleus receives retinal fibers, and that the dorsal division of the facial motor nucleus contains orbicularis oculi motoneurons. Thus, the pretectofacial fibers are assumed to cause protective lid closure with certain visual stimuli.

Identification of a mutagenic substance, in Rubia tinctorum L. (madder) root, as lucidin

Mutagenicity of the extract from Rubia tinctorum L. (madder) root was demonstrated on Salmonella typhimurium TA100 and TA98. The active substance wa purified and characterized by TLC, UV spectrum, IR spectrum, mass spectrum and [1H]NMR spectrum. All the mutagenic activity of the extract from the root of Rubia tinctorum L. was due to lucidin (1,3-dihydroxy,2-hydroxymethyl-9, 10-anthraquinone).

Direct projections from the anterior pretectal nucleus to the dorsal accessory olive in the cat: an anterograde and retrograde WGA-HRP study

Direct projections from the anterior pretectal nucleus (APN) to the dorsal accessory olive (DAO) were found in the cat by the anterograde and retrograde WGA-HRP methods. The dorsal or the ventral portions of the rostral half of the APN pars compacta send fibers respectively to the lateral or the medial portions of the whole rostrocaudal extent of the DAO. These APN-DAO fibers can be considered to play roles in some somatomotor mechanisms.

A light and electron microscopic study of premotor neurons for the trigeminal motor nucleus

Premotor neurons sending their axons to the trigeminal motor nucleus were observed in the cat by light and electron microscopy after labeling the neurons retrogradely or anterogradely with horseradish peroxidase (HRP). After HRP injection into the trigeminal motor nucleus, retrogradely labeled neurons were seen most frequently in the parvocellular reticular formation bilaterally. Many labeled neurons were also seen contralaterally in the intermediate zone at the rostralmost levels of the cervical cord and its rostral extension into the caudalmost levels of the medulla oblongata. Additionally, some neurons were labeled ipsilaterally in the mesencephalic trigeminal nucleus, contralaterally in the main sensory trigeminal nucleus and the trigeminal motor nucleus, and bilaterally in the oral and interpolar subnuclei of the spinal trigeminal nucleus. Only a few labeled neurons were seen in the confines of the gigantocellular reticular formation. All labeled neurons were small or of medium size; no large neurons were labeled. After HRP injection into the regions around the trigeminal motor nucleus or the parvocellular reticular formation, axodendritic terminals containing HRP granules were found contralaterally within the trigeminal motor nucleus. Some of these labeled terminals were filled with round synaptic vesicles and others contained pleomorphic synaptic vesicles. The varied morphology of labeled axon terminals was considered to reflect the functional heterogeneity of the premotor neurons for the trigeminal motor nucleus.

Structural specificity of aromatic compounds with special reference to mutagenic activity in Salmonella typhimurium--a series of chloro- or fluoro-nitrobenzene derivatives

The mutagenicity of 21 chloro- or fluoronitrobenzene compounds and 9 chloro- or fluorobenzene compounds in Salmonella typhimurium (strains TA98, TA1538, TA1537, TA100 and TA1535) was examined. The tests were carried out under the conditions of absence and presence of liver microsomal activation. 15 nitro-group compounds had mutagenic activity; above all, compounds of fluoronitrobenzene were mutagenic for both types of strain. On the other hand, chloronitrobenzene compounds were mutagenic for base-pair substitution strains only. Mutagenic activity was exhibited by all compounds having a chloro or fluoro substituent at the para and ortho position in the nitrobenzene nucleus. All compounds without a nitro substituent showed no mutagenic activity.

Identification of motoneurons supplying the tensor veli palatini muscle in the guinea pig and cat: an horseradish peroxidase study

Identification of motoneurons supplying the tensor veli palatini muscle was attempted by the horseradish peroxidase (HRP) method in the guinea pig and cat. After HRP injection into the tensor veli palatini muscle, HRP-labeled neurons were seen in the regions closely medial to the cluster of the lateral pterygoid motoneurons in the dorsolateral division of the trigeminal motor nucleus. In the guinea pig the tensor veli palatini motoneurons were observed at the level of the whole rostrocaudal extent of the trigeminal motor nucleus, while in the cat they were seen at the level of the rostral two-thirds of the nucleus.

Localization of motoneurons innervating the tensor tympani muscles: an horseradish peroxidase study in the guinea pig and cat

Motoneurons innervating the tensor tympani muscle were identified in the adult guinea pig and cat by the horseradish peroxidase (HRP) method. After HRP injection into the tensor tympani muscle, HRP-labeled neurons were seen in the regions outside the cytoarchitectonically-defined confines of the trigeminal motor nucleus; in the regions rostral to the rostral pole of the nucleus, as well as in the regions ventral and ventrolateral to the nucleus at the levels of the rostral half (guinea pig) or the rostral two-thirds (cat) of the nucleus. The tensor tympani motoneurons were generally smaller than the masticatory motoneurons.

Localization of masticatory motoneurons in the trigeminal motor nucleus of the guinea pig

The myotopical arrangement of masticatory motoneurons was examined in the guinea pig by the horseradish peroxidase method. The trigeminal motor nucleus was composed of dorsolateral and ventromedial divisions; the former was seen in the whole rostrocaudal extent of the nucleus, while the latter was present at levels of the caudal two thirds of the nucleus. The jaw-closer motoneurons were located in the dorsolateral division, and the jaw-opener motoneurons (mylohyoid and anterior digastric motoneurons) were seen in the ventromedial division.

Direct projections from the extrathalamic forebrain structures to the neocortex in the macaque monkey

Extrathalamic direct projections from the subcortical forebrain structures to the neocortex were examined in the macaque monkey by the horseradish peroxidase method. The enzyme, when injected into discrete regions in the neocortex, labeled cell bodies of extrathalamic forebrain neurons in the basal nucleus of Meynert, nucleus of the diagonal band, medial septal nucleus, hypothalamus, claustrum and dorsolateral part of the basal amygdaloid nucleus. Neurons in the basal nucleus of Meynert, lateral hypothalamus and claustrum appeared to send their axons widely, but not diffusely, to the neocortex.