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.

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".

To investigate the exact mechanism of epileptogenesis induced by coriaria lactone (CL), the effect of CL on NMDA receptor mediated current (Iasp) in rat hippocampal CAI neurons was investigated by using nystatin perforated whole-cell patch clamp. 10-6-10-4 mol/L Asp acted on NMDA receptors and elicited an inward current (Iasp) at a holding potential (VH) of -40mV in presence of 10-6 mol/L glycine and absence of Mg2+ extracellularly. CL enhanced NMDA receptor mediated current induced by Asp, but had no effect on threshold concentration, EC50,Hill coefficient as well as maximal-effect concentration and reversal potential of Iasp. The effect had no relationship with holding potential. These results showed that CL could enhance NMDA receptor mediated current to increase [Ca2+]I of neurons by acting on Gly site, thereby inducing epilepsy.

To investigate the exact mechanism of epileptogenesis induced by coriaria lactone (CL), the effect of CL on NMDA receptor mediated current (Iasp) in rat hippocampal CAI neurons was investigated by using nystatin perforated whole-cell patch clamp. 10-6-10-4 mol/L Asp acted on NMDA receptors and elicited an inward current (Iasp) at a holding potential (VH) of -40mV in presence of 10-6 mol/L glycine and absence of Mg2+ extracellularly. CL enhanced NMDA receptor mediated current induced by Asp, but had no effect on threshold concentration, EC50,Hill coefficient as well as maximal-effect concentration and reversal potential of Iasp. The effect had no relationship with holding potential. These results showed that CL could enhance NMDA receptor mediated current to increase [Ca2+]I of neurons by acting on Gly site, thereby inducing epilepsy.

In addition to modulation by a variety of structurally diverse agents that act allosteri-cally via distinct binding sites on the receptor complexes , there is another outstanding characteristic of the GABAA receptors: they are modulated by multiple endogenous agents. Well known examples include Ca2+ , adenosine triphosphate (ATP) , protein kinase A (PKA), protein kinase C(PKC), ty-ros ine kinase (TK) and calmodulin-dependent protein kinase II (CaMK II ). Intracellular modulation of GABAA receptor function may have profound effects on the control of neuronal excitation.

10% and 20% HRP aqueous solution was injected into the anterior wall of the stomach of rabbit, and both the afferent and efferent nerve connections of this region were examined.1. Large number of labeled cells appeared in the dorsal motor nucleus of the vagus nerve (dmnX) on both sides throughout its whole length, except the very rostral and caudal ends of it. The labeled cells were more numerous in the middle part of the nucleus at levels above and below the obex. The distribution of the labeled cells showed certain localization characteristics. Those in the caudal part of the nucleus occupied the medial portion, those in the levels around the obex distributed widely in the nucleus, while in the rostral part they were smaller in number and showed no definite localization.2. In the area between the dorsomedial border of the dmnX and the area pos- trema, the so-called area subpostrema, some disseminated labeled cells, the form of which was similar to that the labeled cells in the dmnX, were also observed.3. Numerous labeled cells appeared in the nodose ganglia on both sides, the number of which was several times more than that in the spinal ganglia, indicating that the afferent connection of the stomach via the vagus nerve predominated over that via the sympathetic nerve. The small-sized labeled cells in the ganglion, however, appeared up to more than 40% of all the labeled cells in it, the functional significance of them, as well as the relation between them and the labeled small cells in the spinal ganglia, is worth further investigation.4. The labeled neurons appeared in the spinal ganglia from Th_3 to L_3, most of them were in Th_3 to Th_(10), showing that the afferents of the stomach via the sympathetic system were diffusely arranged and at the same time concentrated in certain segments.5. Our observations confirmed that the stomach is innervated by elements of bilateral origin. In the vagus system the afferent and efferent neurons appeared almost equally in both dmnX and both nodose ganglia. And in the sympathetic system, the afferent neurons on the left side were 1 to 2 times more than those on the right, i. e., the left side is predominant.

Vmes,

Using Nissl method, Kluver and Barrera method and rapid Golgi method, we found that there were large, medium and small-sized neurons in lamina V of medullary dorsal horn Of the cat, the medium-sized neurons were most numerous and the large-sized neurons were least in number. According to the dendritic branching pattern and the number of spines, the lamina Ⅴ neurons could be divided into two categories——the radiate neuron and bushy neuron. The former contained three subcategories: pyramidal, polygonal and bipolar neurons. Spiny and smooth types were found in pyramidal and polygonal neurons. Considering with the results of neurophysiologic research and intracellular injection of HRP by others, we presume that different types of neurons in lamina Ⅴ might also differ functionally. In addition, according to the results of transganglionic transport of HRP from the peripheral and retrograde transport of HRP from the thalamus, it was assumed that some neurons in lamina V received messages from the primary afferent in lamina Ⅴ, Ⅳ, and Ⅲ, and thence, transmitted them to the thalamus.

The morphological characteristies and distribution of the choline acetyltransferase (ChAT)-like immunoreactive neuronal elements in the sacral and coccygeal spinal cord of the cat were studied by avidin-biotin combined immunohistochemical technique. The results were as follows:1. The ChAT-positive neuronsIn the ventral horn, ChAT-positive motoneurons were located in the motor columns. These neurons can be divided into three types: the large multipolar neurons, the medium-sized multipolar neurons and the small motoneurons. The color of anti-ChAT reaction product in the large and medium-sized motoneurons varied from light to moderate brown, but the small motoneurons were heavily stained.In the intermediate zone, three groups of ChAT-positive parasympathetic preganglionic neurons were observed in 3 areas: the intermediolateral nucleus (IL) in the lateral part of lamina Ⅶ, the intermediomedial nucleus (IM) dorsal-lateral to the central canal, the intercalated nucleus (IC) looated between IL and IM. The somata of these neurons were round, oval, and fusiform in shape. In the lamina Ⅶ, there were some prominent ChAT medium-sized multipolar neurons named partition cells, scattered among the extended fibers of the parasympathetic preganglionic cells. In the vicinity of the central canal could be observed small CHATpositive cells.In the ventral part of the dorsal commissural nucleus region, a number of ChAT-positive cells were present. They were round, oval and fusiform in shape and small in size (averaging 11.91?m?17.38?m). Occasionally, they were observed in the dorsal part.In addition, some of the ChAT-positive neurons were scattered in laminae Ⅲ-Ⅴ.2. The ChAT-positive fibers and terminals.The ChAT-positive punctate structures were observed throughout the sacral and coccygeal spinal cord resembling terminal branch and terminals. The density of the distribution of the punctate structures was arranged, from high to low, in the following order: the ventral horn, intermediate zone, central gray matter and dorsal commissural nucleus region, and the dorsal horn. In the dorsal horn, many of these punctate structures Were concentrated in two laminae, the major one being lamina Ⅲ and a minor one lamina Ⅰ. But in lamina Ⅱ, they were rare. In the ventral horn such punctate structures were often closely contacted with large and medium-sized ChAT-positive motoneuronal somata and dendrites. Some axonal terminal branch with varicosities closely surrounded a somata and bases of dendrites, and formed contacts with the same somata and its dendrites. In the intermediate zone, there were many transverse fibers associated among the parasympathetic preganglionic nuclei.

HRP solution was injected into the dorsal commissural nucleus (DCN) of segment L_6 or S_1 of the spinal cord and laterodorsal tegmental area(TLD)——take the Barrington's nucleus as its center and lateral parabrachial nucleus (PBL) of the rostral pons in different individuals of the rats. After HRP was injected into the DCN, labelled neurons and dense terminals were found in Barrington's nucleus, and labelled terminals appeared in the PBL. When the unilateral TLD was injected the labelled cells and terminals were found in the DCN and bilateral intermediate zone (IM), and formed a band of labelled neurons and terminals. When the PBL was injected the labelled neurons were observed in the DCN and bilateral IM. A few labelled neurons were found in lamina Ⅰ in the latter two experimental groups.Based on the present and previous studies, the authors got the following understandings:1. Morphylogically, the present study for the first time demonstrated that, the micturition reflex arch through the pontine consists of following parts: the primary afferent neurons of the bladder→secondary relay neurons of DCN→Barrington's nucleus→IM (mainly IML) parasympathetic preganglionic neurons→parasympathetic postganglionic neurons.2. According to the present and previous researches, the authors conjecture that, the secondary fibers of visceral sensation of the pelvic organs originate from the neurons of DCN, IM and lamina I and project into the PBL.3. According to the facts mentioned above, we presume that the DCN and bilateral IM constitute a complex and named it the 'visceral field', and which is closely associated with the pelvic organs. This field has widespread connections with the peripheral efferent and afferent nerves. On the other hand, i t contains a lot of relay neurons projecting into Barrington's nucleus and PBL and receives the terminals of descending fibers of the neurons of the Barrington's nucleus. The descending fibers also project into the Onuf's nucleus.In addition, the present study disscussed the complicated functions of the DCN systematically.