NEURAL PATHWAYS OF TRIGEMINAL PROPRIOCEPTIVE AFFERENTS COORDINATE ORAL MOTOR BEHAVIORS / 神经解剖学杂志

Neural pathways and synaptic connections from the trigeminal mesencephalic nucleus (Vme) neurons to the cranial motor nuclei were studied in the rat using double labelling methodologies of intracellular Neurobiotin staining combined with retrograde horseradish peroxidase (HRP) transport, anterograde biotinylated dextran amine (BDA) tracing combined with retrograde HRP transport, and a dual fluorescent labelling of BDA anterograde combined tracing with Cholera Toxin B (CTB) retrograde transport. Direct projections and synapses were demonstrated from Vme neuronal boutons to motoneurons (MNs) of the trigeminal motor nucleus (Vmo), the hypoglossal nucleus (Ⅻ) and the ambiguus nucleus (Amb). Indirect projections and pathways from Vme neurons to the cranial motor nuclei including Vmo, Ⅻ, the facial nucleus (Ⅶ) and the cervical spinal cord (C1～5) were seen to relay on their premotor neurons. The premotor neurons of above cranial motor nuclei were overlapped in bilateral premotor neuronal pool including the parvocellular reticular formation (PCRt) and its alpha division (PCRtA), the dorsomedial part of the spinal trigeminal nucleus oralis (Vodm), and interpolaris (Vidm), the medullary reticular nucleus dorsal division (MdD), the supratrigeminal region (Vsup) and the dorsomedial part of the principal trigeminal sensory nucleus (Vpdm).Synapses between Vme neuronal boutons and Vmo and Ⅻ MNs and Ⅻ premotor neurons were predominantly asymmetric.There were four types of synaptic organizations, i.e. synaptic convergence; synaptic divergence presynaptic inhibition and afferent feedforward inhibition seen between Vme boutons and Vmno, Ⅻ MNs and between Vme boutons and Ⅻ premotor neurons.The results of present studies have demonstrated direct pathways from the trigeminal proprioceptive afferents to Vmo, Ⅻ and Amb MNs, and indirect pathways from the trigeminal proprioceptive afferents to bilateral Vmno, Ⅻ, Ⅶ and C1～s via their premotor neurons. It provides neuroanatomical network to elucidate trigeminal proprioceptive afferents coordinate oral motor behaviors.

CONNECTIONS BET WEEN VESICULAR GLUTAMATE TRANSPORTERS-,GAD-LIKE IMMUNOREACTIVE TERMINALS AND GABA_A RECEPTOR ?3 SUBUNIT- LIKE POSITIVE NEURONS IN MESENCEPHALIC TRIGEMINAL NUCLEUS OF THE RAT / 解剖学报

Objective To observe the association of vesicular glutamate transporter of typeⅠ (VGluT1 ) like immunoreactive(LI) ,the differentiation-associated Na+ dependent inorganic phosphate cotransporter(DNPI) LI and glutami cacid decarboxy lase(GAD) LI terminals with GABAA receptor ?3 subunit(GABAAR ?3) LI neurons in mesencephalic trige minal nucleus of the rat.Methods Triple immun of luorescencehis to chemical staining technique and confo call aser scanning micros copy were used.Results Alargenumber of neuronal cell bodies showed GABAA R?3 LI immunoreactivity atallrostrocaudal level softhe Vme ,and most of GABAAR ?3 LI cells were large (2 5 5 0 ?m)pseudouni polarneurons.The dense VGluT1 LI,DNPL LI and GAD LIterminal sdistri buted widelyin Vme ,some VGlu T1 DNPI LI and GAD LIterminals surrounded the somata of the GABAAR ?3 LI Vmeneurons ,and made close contacts with them .Conclusion Proprioceptive sensory signals from the or of acialregionmight be modulated at the level of the primary afferent cell bodies in the Vme both by glutamatergic and GABAergic axonal terminals from other brain areas,and the effect of GABAergic terminals might be mediated by post synaptical GABAA receptors .

PARVALBUMIN-EXPRESSING NEURONS ON THE CENTRAL PATHWAY OF THE TRIGEMINAL PROPRIOCEPTIVE SENSATION OF THE RAT: A DOUBLE LABELING STUDY / 神经解剖学杂志

Previous studies showed that the Vodm-LRF-including the dorsomedial part of the subnucleus oralis of the spinal trigeminal nucleus and its adjacent lateral reticular formation--contained the second-order neurons on the central pathway of the trigeminal proprioceptive sensation of the rat and the "zone-shaped area"-including the caudolateral part of the supratrigeminal nucleus (Vsup-CL). The dorsomedial part of principal sensory trigeminal nucleus (Vpdm) and two newly found nuclei: the areaventral to the motor trigeminal nucleus (AVM) and the area dorsal to the superior olivary nucleus (ADO)-contained the third order neurons of this pathway. Parvalbumin (PV) is one of the calcium-binding proteins, In this pathway, many PV-like immunoreactive (PV-LI) neurons were observed in Vodm LRF and the "zone-shaped arena", hut there has been no reports so far regarding whether these PV-LI neurons are projection neurons responsible for the transmission of proprioceptive information or the interneurons serving the modulatory function, in the present study, our aim was to solve the problem by a double labeling study by using retrograde tracing method combined with immunofluorescence histochemistry. The results showed that: (1) following the unilateral Fluoro-Gold (FG) injections into the ventral posteromedial nucleus (VPM) of the thalamus and the separated parts of the "zone-shaped area", viz, Vpdm, ADO and AVM, many FG-labeled neurons were always found contralaterally in the "zone-shaped area" and ipsilaterally in the Vodm-LRF, respectively; (2) in either the "zone-shaped area" or the Vodm-LRF, a substantial number of the FG retrogradely labeled neurons showed PV-LI. In the Vsup-CL, Vpdm, AVM and ADO, about 57%, 55%, 11% and 4% of the neurons projecting to the VPM of the thalamus showed pV-LI, respectively. Of the total population of PV-LI neurons in the Vsup-CL, Vpdm. AVM and ADO, about 23%, 79%, 53% and 16% were labeled by FG, respectively. Most of these PV/FG double-labeled neurons were medium- to small-sized, round, piriform or irregular in shape. On the other hand, in the Vodm-LRF, approximately 33%, 34% and 50% of the neurons which projected to the Vpdm, AVM and ADO expressed PV-LI, respectively. The percentage of PV/FG double-labeled neurons to the total number of the PV-LI neurons in Vpdm, AVM or ADO were 26%, 17% or 11%, respectively, The present results indicated that PV might play an important role in the transmission of the trigeminal proprioceptive information of the rat from Vndm-LRF to the contralateral VPM of the thalamus through the "zone-shaped area".

EXPRESSION OF TrkA, TrkB and TrkC RECEPTORS IN THE CENTRAL PATHWAY OF TRIGEMINAL PROPRIOCEPTION IN THE RAT / 解剖学报

Objective To examine the distribution of high-affinity neurotrophin receptors, viz. TrkA, TrkB and TrkC receptors, in the four-order central pathway of trigeminal proprioception in the rat. Methods Avidin-biotin-peroxidase complex (ABC) method of immunohistochemistry with diaminobenzidine (DAB) as the chromogen was employed to identify the immunoreactive cells. Results All three receptors were detected in the mesencephalic trigeminal nucleus, the second-and third-order nuclei in the central pathway of trigeminal proprioception. Within each of these nuclei, cells immunostained for the three receptors differed in density. TrkA-and TrkB-immunostaining was observed on the cell bodies and processes; TrkB, however, labelled much longer processes. TrkC staining was mainly restricted to the cell bodies.Conclusion In the central pathway of the trigeminal proprioception, each of the three receptors may play a specific role in maintaining the survival of neurons and in regulating the neurotransmitter release.;

ULTRASTRUCTURAL EVIDENCE OF SEROTONINERGIC INNERVATION OF THE SECONDORDER NEURONS ON THE CENTRAL PATHWAY OF THE TRIGEMINAL PROPRIOCEPTION OF THE RAT / 解剖学报

Objective To investigate whether the serotonin(5\|HT)\|like immunoreactive axons synapse upon the second\|order neurons on the central pathway of the trigeminal proprioception in the rat. Methods Electron microscopic double\|labeling of retrograde tract\|tracing technique combined with immunohistochemistry. Results Following the injection of wheat germ agglutinin\|horseradish peroxidase (WGA\|HRP) into the dorsomedial part of the principal sensory trigeminal nucleus(Vpdm) of the rat and the immunostaining for 5\|HT, there were neurons retrogradely labeled by WGA\|HRP and axon terminals with 5\|HT\|like immunoreactivity(5\|HT\|LI) in the dorsomedial part of the subnucleus oralis of the spinal trigeminal nucleus and its adjacent lateral reticular formation(Vodm\|LRF).At the electron microscopic level,the 5\|HT\|immunostained axonal profiles were observed to make synaptic contacts with the WGA\|HRP\|labeled neurons.Both the axon\|somatic and axon\|dendritic synapses were found.These synapses were mainly of symmetric type although the asymmetric ones were also seen.Conclusion\ The present results provided a morphologic basis for the serotoninergic terminals which might be involved in the regulatory effect for the trigeminal proprioceptive information transmission.\;[