Arrangement and Connections of Mesencephalic Trigeminal Neurons in the Rat

Rokx, J.T.M.; Jüch, P.J.W.; Willigen, J.D. van

doi:10.1159/000146233

Cited by 52 publications

(26 citation statements)

References 10 publications

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“…Anatomical studies have provided supporting evidence to indicate that the PCRt and PCRtA play a major role in orofacial motor behavior (Hamilton and Norgren, 1984;Rokx et al, 1985;Rokx and van Willigen, 1988;Jü ch and Rokx, 1988;Pfaller and Arvidsson, 1988;ter Horst et al, 1991). The PCRt and PCRtA receive afferent inputs from the oral cavity and jaw musculature (Hamilton and Norgren, 1984;Pfaller and Arvidsson, 1988) and have reciprocal connections with the mesencephalic trigeminal nucleus (Rokx et al, 1985;Jü ch and Rokx, 1988;Rokx and van Willigen, 1988).…”

Section: Functional Considerationsmentioning

confidence: 98%

Trigeminal-reticular connections: Possible pathways for nociception-induced cardiovascular reflex responses in the rat

1998

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Cardiovascular regulatory neurons of the ventral medulla and pons are thought to have an important role in the mediation of trigeminal nociception-induced reflex cardiovascular responses. However, the neural pathways that link the spinal trigeminal nucleus with ventral medullary and pontine autonomic cell groups are poorly understood. The present study utilized injections of the highly sensitive anterograde tracer substance biotinylated dextran combined with immunocytochemistry for tyrosine hydroxylase, the synthesizing enzyme for catecholamines, to investigate the distribution and morphology of projections from the spinal trigeminal subnucleus caudalis to ventral medullary and pontine catecholaminergic cell groups. Injection of biotylinated dextran into the dorsal subnucleus caudalis produced dense anterograde labeling in dorsal regions of the medullary and pontine reticular formation including the dorsal medullary reticular field, the parvicellular reticular field, and the parvicellular reticular field pars anterior. In the ventral medullary and pontine reticular formation, light anterograde labeling tended to be distributed in close proximity to the distal dendrites of catecholaminergic neurons located in the C1, A1, and A5 regions. Injections of anterograde tracer into the dorsal medullary reticular field produced dense anterograde labeling in the ventral medullary and pontine reticular formation. Numerous terminal-like varicosities were observed in close proximity to catecholaminergic neurons located in the C1, A1, and A5 regions. These data suggest that trigeminal pain-induced reflex cardiovascular responses involve indirect projections that terminate in the dorsal medullary and pontine reticular formation before reaching ventral medullary and pontine catecholaminergic cell groups known to be involved in cardiovascular regulation.

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Section: Functional Considerationsmentioning

confidence: 98%

Trigeminal-reticular connections: Possible pathways for nociception-induced cardiovascular reflex responses in the rat

1998

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“…Rokx et al, 1986], there are two differences. The first is that birds lack teeth and do not have periodontal sense organs innervated by mesV.…”

Section: Sensory Input To the Reticular Premotor Areasmentioning

confidence: 98%

The Neural Substrate for ‘Learned’ and ‘Nonlearned’ Activities in Birds: A Discussion of the Organization of Bulbar Reticular Premotor Systems with Side-Lights on the Mammalian Situation

Dubbeldam¹

1998

Cells Tissues Organs

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The reticular formation of the brainstem contains premotor systems for various musculomotor systems. In this paper, the bulbar premotor systems for jaw and tongue movements, head and neck movements, locomotion, and respiration and vocalization in birds are reviewed and compared to premotor systems in mammals. Roughly, the bulbar reticular formation can be subdivided in three longitudinal zones: a dorsolateral (RPcdl) and a ventromedial (RPcvm) parvocellular zone and a gigantocellular zone (RGc). RPcdl contains premotor neurons for the jaw and neck system, RPcvm for the jaw, tongue and neck system, and RGc for the tongue and locomotory system. RPcdl receives input from the descending sensory trigeminal system, parts of RPcvm and RGc from vestibular nuclei, whereas the tectum has a projection to the contralateral RGc. RPcdl and RPcvm receive substantial telencephalic input through the occipitomesencephalic tract. The bulbar part of the respiratory system consists of a series of cell groups in the ventrolateral reticular formation and has connections with motor centers of the vocalization system. The similarities and differences between the avian and mammalian situation are discussed. Musculomotor systems participate in various activities. It is argued that a premotor system should possess sufficient flexibility to control the participation of a motor system in the different activities. This flexibility may permit the occurrence of learning processes in terms of refining basically existing motor patterns. The emergence of new and more complex motor patterns as in vocalization requires the involvement of hierarchically higher brain centers.

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“…The scattered neurons of the mes5, concentrated near the aqueduct in the caudal midbrain, provide sensory innervation of the masticatory muscles and teeth and constitute the only sensory neurons (exclusive of special senses) located within the CNS (Rokx et al, 1986). Thus, these neurons provide a test of whether the Brn3a regulatory sequences contained in the 11 kb/LacZ reporter direct expression to the sensory ganglia based on anatomical location in the PNS or to a functionally similar class of neurons independent of location.…”

Section: The Brn3a Locus Contains Regulatory Sequences Specific For Smentioning

confidence: 99%

Defects in Sensory Axon Growth Precede Neuronal Death in Brn3a-Deficient Mice

Eng¹,

Gratwick²,

Rhee³

et al. 2001

J. Neurosci.

112

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Brn3a/Brn-3.0 is a POU-domain transcription factor expressed in primary sensory neurons of the cranial and dorsal root ganglia and in specific neurons in the caudal CNS. Mice lacking Brn3a undergo extensive sensory neural death late in gestation and die at birth. To further examine Brn3a expression and the abnormalities that accompany its absence, we constructed a transgene containing 11 kb of Brn3a upstream regulatory sequence linked to a LacZ reporter. Here we show that these regulatory sequences direct transgene expression specifically to Brn3a peripheral sensory neurons of the cranial and dorsal root ganglia. Furthermore, expression of the 11 kb/LacZ reporter in the sensory neurons of the mesencephalic trigeminal, but not other Brn3a midbrain neurons, demonstrates that cellspecific transgene expression is targeted to a functional class of neurons rather than to an anatomical region. We then interbred the 11 kb/LacZ reporter strain with mice carrying a null mutant allele of Brn3a to generate 11 kb/LacZ, Brn3a knockout mice. ␤-Galactosidase expression in these mice reveals significant axonal growth defects, including excessive and premature branching of the major divisions of the trigeminal nerve and a failure to correctly innervate whisker follicles, all of which precede sensory neural death in these mice. These defects in Brn3a Ϫ/Ϫ mice resemble strongly those seen in mice lacking the mediators of sensory pathfinding semaphorin 3A and neuropilin-1. Here we show, however, that sensory neurons are able to express neuropilin-1 in the absence of Brn3a. Key words: POU-domain; homeodomain; Brn3; TrkC; trigeminal ganglion; sensory ganglion; axon guidanceThe vertebrate nervous system contains a large number of specific cell types, and how this neuronal diversity is generated is a central question in the study of brain development. Many neurons in the developing brain can be recognized by the expression of specific "neural identity" genes that are first detectable at approximately the time of exit from cell division and may persist throughout embryogenesis. Most such genes discovered to date have been transcription factors, often but not always containing a homeodomain motif (Rubenstein and Puelles, 1994). A specific neural identity gene may be expressed in a recognizable class of neurons, such as the motor neurons of the brainstem and spinal cord, or it may characterize a group of cells that have no other known features in common. Accordingly, they are good candidates for establishing the neuronal phenotypes characterized by, among others, the cellspecific expression of neurotransmitters and their receptors, axonal guidance to selected targets, and synaptic specificity. However, the neuronal properties that are actually regulated by these factors, and how this regulation is accomplished, remain primarily undiscovered.The "Brn3" or POU-IV class of transcription factors is comprised of three members in vertebrates that share very similar DNA recognition properties to their invertebrate counterparts (Gruber et al., 199...

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Arrangement and Connections of Mesencephalic Trigeminal Neurons in the Rat

Cited by 52 publications

References 10 publications

Trigeminal-reticular connections: Possible pathways for nociception-induced cardiovascular reflex responses in the rat

Trigeminal-reticular connections: Possible pathways for nociception-induced cardiovascular reflex responses in the rat

The Neural Substrate for ‘Learned’ and ‘Nonlearned’ Activities in Birds: A Discussion of the Organization of Bulbar Reticular Premotor Systems with Side-Lights on the Mammalian Situation

Defects in Sensory Axon Growth Precede Neuronal Death in Brn3a-Deficient Mice

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