RESUMEN
Objective To observe the relationships among the direct projection neurons from the lumbar spinal cord to the lateral parabrachial nucleus(LPB),calbindin D-28K(CB)-like immunoreactive (-LI) neurons,peripheral noxious information transmission as well as substance P receptor(SPR)-LI neurons. Methods Triple-labeled techniques were used by tetramethyl rhodamine(TMR) retrograde tracing combined with immunofluorescence histochemistry for CB-,SPR- or Fos protein.The stained sections were observed under a confocal laser-scanning microscope. Results 1.After injecting TMR to the unilateral LPB,a number of TMR retrogradely labeled neurons were mainly distributed in the lamina Ⅰ,lateral spinal nucleus(LSN),and regions around the central canal of the spinal cord(lamina X) of the ipsilateral spinal cord;2.CB-LI neurons were mainly found in the laminae Ⅰ and Ⅱ of the lumbar spinal cord,especially in the lamina Ⅱ in the dense distribution; 3.SPR-LI neurons were also mainly seen in the lamina Ⅰ,LSN and lamina X of the spinal cord.A few of the SPR-LI neurons were also distributed in the lamina Ⅱ;4.Fos-positive neurons were detected in the laminae Ⅰ and Ⅱ,lateral aspect of the lamina Ⅴ to Ⅶ of the lumbar spinal cord by injecting 5% formalin into the ipsilateral hindpaw;5.Triple-labeled neurons for TMR/CB/SPR or TMR/CB/Fos were mainly found in lamina Ⅰ,while a few of the triple-labeled neurons were also found in lamina Ⅱ of the dorsal horn.TMR/CB/SPR triple-labeled neurons accounted for 103%,98% and 146% of total population of TMR-,CB- or SPR-LI neurons in laminae Ⅰ and Ⅱ,respectively.On the other hand,TMR/CB/Fos triple-labeled neurons formed 118%,106% and 158% of the total population of TMR-,CB-LI or Fos-positive neurons in the laminae Ⅰ and Ⅱ,respectively.Conclusion\ The results indicated that in the laminae Ⅰ and Ⅱ of the lumbar spinal cord some neurons with CB-Like immunoreactivity transmitting the peripheral noxious information and projecting directly to the LPB might receive SPergic primary afferents.
RESUMEN
The present experiments were designed to study the afferent connections of the oval nucleus (Ov) of the bed nuclei of the stria terminalis (BST) using fluoro-gold (FG) and WGA-HRP as retrograde tracers. After injection of FG or WGA-HRP into the Ov area of the male SpragueDawley rats, a number of retrogradely labeled neurons were observed in the piriform cortex, fundus striati, subiculum, preoptie areas, horizontal limb of the diagonal band, ventral pallidum, magnocellular preoptic area, central (Ce), medial and cortical nuclei of the amygdala. A few neurons in the midline nuclei of the thalamus. were labeled. Many labeled neurons were found in the anterior, dorsal and lateral hypothalamic areas, ventral medial, arcuate and premammillary nuclei of the hypo thalamus. In the brainstem many labeled neurons were seen in the ventral part of the midbrain central gray, dorsal raphe nucleus, pedunculopontine tegmental nucleus, ventral tegmental area, compact zone of the substantia nigra, interpeduncular nuclei, interfascicular nucleus, raphe nuclei, parabrachial nuclei, locus coeruleus, mesencephalie trigeminal nucleus, dorsal vagal complex, A_5 and A_1 cell groups.In general, the distribution patterns of the labeled neurons of both tracers were quite similar except that FG labeled neurons showed much longer processes than WGA-HRP's, and some FG labeled neurons were also found in a few contralateral structures, such as central and medial nuclei of the amygdala and the horizontal limb of the diagonal band, where no WGA-HRP labeled neurons were observed.The results of this retrograde tract-tracing study together with our previous. anterograde tract-tracing study indicate that there are reciprocal connections between the Ov and the Ce, posterior part of the lateral hypothalamus and several brainstem structures.
RESUMEN
In this study a combination of HRP retrograde tract tracing and immunocytochemistry was employed to investigate the afferent projections of neuropeptide Y(NPY) -and neurotensin (NT)-immunoreactive(ir) neurons in the cervical, thoracic, lumbar and sacral spinal segments to the parabrachial nucleus in the rat. It was demonstrated that the retrogradely labeled neurons were scattered in bilateral laminae I, II, IV, V, VII, gray matter commissure dorsal to the central canal, lateral cervical nucleus and lateral spinal nucleus. The NPY-ir neurons were situated in bilateral lamina I, superficial portion of the lamina II, lateral cervical nucleus and lateral spinal nucleus. The NT-ir cells were seen in bilateral lamina I and lamina II of dorsal horn. In lamina I, lateral cervical nucleus and lateral spinal nucleus a few of NPY-HRP double labelled neurons could be observed. Individuals of NT-HRP double labeled neurons were identified only in lamina I. The results of this study suggest that NPY and NT neurons probably involved in the nociceptive transmission of the spino-parabrachial pathway.
RESUMEN
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.\;[