The central projections of visceral primary afferent neurons of the inferior mesenteric plexus and hypogastric nerve and the location of the related sensory and preganglionic sympathetic cell bodies in the rat

Summary The central projections of visceral primary afferents of the inferior mesenteric plexus and hypogastric nerve of the rat were investigated using the transganglionic transport of horseradish peroxidase (HRP). In addition, the location of the corresponding spinal ganglion cells as well as the preganglionic sympathetic neurons is demonstrated.Labelled afferent axons were found in dorsal roots, dorsal root entry zone (preferentially in its lateral part), in all parts of the tract of Lissauer, and in the dorsolateral funiculus. Preterminal axons and/or terminals were distributed mainly to laminae I, IIa and the nucleus of the dorsolateral funiculus. Fewer afferents reached laminae IIb, III–V and X. Afferent projections are densest at L1 and 2 and the caudal T13, but extend up to T10 rostrally, and at least down to L4 caudally. A few visceral afferents ascend to the nucleus gracilis.The great majority of sensory and preganglionic sympathetic cell bodies is located at levels L1 and 2 bilaterally. A few cells are found in decreasing numbers rostrally up to T11.Preganglionic sympathetic neurons (PSN) are located in nucleus intermediolateralis (IML), n. intercalatus (IC) and n. commissuralis dorsalis (DCN). Axons of DCN and IC neurons run laterally, joining those of IML neurons on their way to the ventral roots. Dendrites of IML neurons ramify in all directions but preferentially to the dorsal horn and dorsolateral funiculus. Dendrites of IC and DCN neurons are distributed mainly mediolaterally, the latter also ventrally around the canalis centralis.     

大鼠腰骼髓“内脏面”传出和上行投射神经元的定位分布——HRP与荧光金追踪法研究

用HRP与荧光金(FG)结合的示踪法,观察了大鼠腰骶髓“内脏面”副交感节前神经元和上行投射神经元的定位分布。发现FG注入一侧臂旁外侧核或Barrington核后,逆行标记的金色荧光细胞出现于双侧L_5～S_2的“内脏面”,细胞密集于后连合核和中间带外侧核(IML),此外,还出现于双侧的I层及外侧脊髓核(LSN)。HRP注射于一侧盆神经后,逆标细胞出现于术侧的L_6和S的IML,偶见于中介核(IC)。在IML内,HRP标记的副交感节前神经元位于其腹侧份,而FG标记的上行投射神经元主要位于背侧和背内侧部,亦可见少数FG标记细胞混杂在HRP标记细胞之间。本研究结合已有的研究对IML的命名、组成和功能以及LSN的组成进行了讨论。     

Calcitonin gene-related peptide-like immunoreactivity in spinal cord and superior cervical ganglion of the djungarian hamster (Phodopus sungorus)

The indirect immunofluorescent method was employed to investigate the distribution of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) in the spinal cord and superior cervical ganglion of the Djungarian hamster Phodopus sungorus. In cross-sections of the spinal cord, immunoreactive fibres and terminals were found in laminae 1 and 2 in high density, in the dorsolateral (Lissauer's) tract, in ventral and lateral horns, and in the area surrounding the central canal. A few CGRP-LI perikarya were seen in the ventral but not the dorsal horn. CGRP-LI was further observed in preganglionic sympathetic neurons which were labelled by retrograde axonal transport of fluoro-gold (FG) following injection of the substance unilaterally into the superior cervical ganglion. Preganglionic sympathetic neurons (PSN) were localized ipsilateral to the injection site mainly in the intermediolateral nucleus and the lateral funiculus of the upper thoracic segments. Most PSN exhibited CGRP-LI. Immunoreactive PSN were not seen contralaterally to the site of FG application nor in animals that did not receive injections. When the preganglionic fibres were ligated 4 days before perfusion. CGRP-LI cell bodies were found in preganglionic sympathetic neurons similar to the situation seen upon FG treatment.

In the superior cervical ganglia of untreated hamsters, immunoreactive fibres were seen to enter the ganglion in which they terminated at non-immunoreactive principal ganglion cells.

The present study, the first in a hamster species, describes the widespread distribution of CGRP in the spinal cord of P. sungorus and supports the view that considerable interspecies differences exist in occurrence and location of this neuropeptide.     

大鼠脊髓内接受盆腔脏器伤害性刺激神经元的定位分布

本文用Ｆｏｓ蛋白免疫组织化学方法研究了大鼠脊髓内接受盆腔脏器伤害性刺激神经元的分布状况。在对照组，仅偶见Ｆｏｓ阳性细胞出现于Ｌ６、Ｓ１节段脊髓后角（＜２个／片），且染色浅淡。将３％福尔马林经插管分别注入膀胱、阴道和直肠造成伤害性刺激时，Ｆｏｓ阳性细胞数明显增多（１００～２６０个／片，Ｓ１），主要出现于Ｌ６、Ｓ１节段后角Ⅰ层内侧部、后角内侧缘、后连合核和中间带外侧核。少量散在于后角Ⅰ层外侧部、后角外侧缘、外侧脊核和前角背内侧部。为了确定脊髓内Ｆｏｓ阳性神经元是否向上位脑结构投射，将荧光金（ＦＧ）注入一侧臂旁外侧核后，给予膀胱伤害性刺激，结合Ｆｏｓ蛋白免疫组化技术，在后连合核和中间带外侧核发现有ＦＧ／Ｆｏｓ双标细胞。在中间带外侧核，ＦＧ标记细胞与Ｆｏｓ阳性细胞均主要位于核的背侧部，且ＦＧ标记细胞多数同时为Ｆｏｓ阳性，ＦＧ／Ｆｏｓ双标细胞占ＦＧ标记细胞总数的７１．２％（３７／５２），占Ｆｏｓ阳性细胞总数的１４．８％（３７／２５０），提示脊髓内接受盆腔脏器伤害性神经元部分投射至臂旁外侧核。为进一步确定Ｆｏｓ阳性细胞在中间带外侧核定位分布特征，采用ＮＡＤＰＨ脱氢酶反应（显示副交感节前神经元）与Ｆｏｓ蛋白免疫组化相结合?     

Nitric oxide synthase immunoreactivity in rat spinal cord.

Immunoreactivity to nitric oxide synthase (NOS-IR) and choline acetyltransferase (ChAT-IR) was detected in the adult rat spinal cord using the avidin-biotin-peroxidase technique. Intensely stained NOS-positive neurons with cell processes were observed in the intermediolateral cell column of the thoracic and sacral segments and around the central canal of all segments. These areas also contained ChAT-IR neurons. A number of small- to medium-sized NOS-IR cells were noted in the superficial and deeper laminae throughout the entire cord. NOS-IR was not detected in the ventral horn motoneurons, which were, however, ChAT-IR. The results indicate that NOS-IR is present in autonomic preganglionic neurons and in selected neurons in the dorsal horn and lamina X, but appears to be absent in motoneurons.     

Patterns of colocalization of neuronal nitric oxide synthase and somatostatin-like immunoreactivity in the mouse hippocampus: quantitative analysis with optical disector

In some brain regions, previous studies reported the frequent coexistence between neuronal nitric oxide synthase (nNOS) and somatostatin (SOM). In the hippocampus, nNOS and SOM were mainly expressed in GABAergic nonprincipal neurons. Here we estimated the immunocytochemical colocalization of nNOS and SOM in the mouse hippocampus using the optical disector. Both in the Ammon's horn and dentate gyrus, we encountered only a few nNOS-immunoreactive (IR)/SOM-like immunoreactive (LIR) neurons. They were mainly located in the stratum oriens of the Ammon's horn and in the dentate hilus. The nNOS-IR/SOM-LIR neurons usually showed characteristic large somata with thick dendrites, whereas the majority of nNOS-IR/SOM-negative neurons showed small somata with thin dendrites. Quantitative data revealed that the double-labeled cells represented only 4% and 7% of nNOS-IR neurons and SOM-LIR neurons, respectively, in the whole area of the hippocampus. We also found the laminar and dorsoventral differences in the degree of colocalization between nNOS and SOM. The percentages of nNOS-IR neurons containing SOM-like immunoreactivity were relatively high in the stratum oriens of the ventral CA1 region (24%), stratum lucidum of the dorsal CA3 region (29%) and dorsal dentate hilus (32%), but they were quite low in the other layers. On the other hand, the percentages of SOM-LIR neurons containing nNOS immunoreactivity were somewhat high in the stratum lucidum of the dorsal CA3 region (19%) and dorsal dentate hilus (28%), whereas they were very low in the other layers. Immunofluorescent triple labeling of axon terminals for nNOS, SOM and glutamic acid decarboxylase indicated that some nNOS-IR/SOM-LIR neurons might be dendritic inhibitory cells. The present results show the infrequent colocalization of nNOS and SOM in the mouse hippocampus, and also suggest that the double-labeled cells may be a particular subpopulation of hippocampal GABAergic nonprincipal neurons.     

5-羟色胺在大鼠腰骶髓后连合核和中间带外侧核参与盆腔内脏炎性痛调控的形态学研究

本研究运用荧光金(FG)逆行束路追踪与5-HT1A受体免疫荧光组织化学染色技术相结合,观察了大鼠腰骶髓后连合核(DCN)和中间带外侧核(IML)内感受盆腔内脏伤害性信息并向外侧臂旁核(LPB)发出投射的神经元呈5-HT1A受体免疫反应阳性。将FG注入一侧LPB后,可在腰骶节段(L6-S2)观察到大量的FG逆标神经元,这些FG逆标神经元主要集中于DCN和IML内,以同侧为主;5%福尔马林注入大鼠结肠后,Fos蛋白阳性神经元主要分布于腰骶髓DCN和IML,以同侧为主,在同侧脊髓背角I层、II层和深层也有少量的分布。另外,在腰骶髓DCN和IML内,还可观察到大量5-HT1A受体阳性的神经元胞体、纤维和终末,同时有部分Fos蛋白阳性的FG逆标神经元呈5-HT1A受体阳性。上述结果提示,大鼠腰骶髓DCN和IML内的5-HT能终末可能对盆腔内脏伤害性信息的传递发挥调控作用。     

Location of bladder preganglionic neurons within the sacral parasympathetic nucleus of the cat.

Sacral parasympathetic preganglionic neurons innervating the urinary bladder were labelled by applying horseradish peroxidase (HRP) to branches of the pelvic nerve at the neck of the bladder. Bladder preganglionic cells were located primarily in the intermediolateral grey matter of sacral cord segments 1, 2 and 3 and extended from the ventral end of the central canal to the inferior margin of the dorsal horn. Dendrites extended into the dorsolateral funiculus, toward the lateral edge of the dorsal horn, medially beneath the dorsal horn and ventrally within the nucleus. Although a small number of cells were found medially beneath the dorsal horn, it is concluded that the majority of bladder preganglionic neurons occupy a lateral position within the sacral parasympathetic nucleus.     

nNOS阳性神经元支配雄性大鼠球海绵体肌和坐骨海绵体肌

为了证实一氧化氮是否参与调节球海绵体肌和坐骨海绵体肌的功能 ,本研究用 CB-HRP逆行追踪结合 n NOS免疫细胞化学的技术 ,对支配雄性大鼠球海绵体肌和坐骨海绵体肌的神经元进行了研究 ,并结合 NADPH-d组化技术对雄性大鼠腰、骶髓的 NADPH-d阳性细胞和突起的分布进行了观察。结果发现 :( 1)支配球海绵体肌和坐骨海绵体肌的 Onuf核内存在着 CB-HRP与 n NOS双重反应细胞、CB-HRP阳性细胞、n NOS阳性细胞 ;n NOS阳性细胞还可见于后连合核、骶副交感核、背角等部位。( 2 ) NADPH-d阳性神经元在腰、骶髓主要位于中央管周围、后连合核、骶副交感核、背角等部位。本研究为 NO作为神经活性物质参与球海绵体肌和坐骨海绵体肌功能的调节提供了形态学证据     

Descending input from the hypothalamic paraventricular nucleus to sympathetic preganglionic neurons in the rat

Summary The descending projection of the hypothalamic paraventricular nucleus (PVN) to the sympathetic preganglionic neurons (SPNs) in the upper thoracic cord of the rat was studied. PVN-fibers were labeled by anterograde transport of Phaseolus vulgaris leucoagglutinin (PHA-L), while SPNs were retrogradely labeled with cholera toxin subunit B (CTb) which was injected into the superior cervical ganglion. SPNs labeled with CTb were mainly observed in the nucleus intermediolateralis (IML) pars principalis and pars funicularis, and a small number of them were in the nucleus intercalatus (IC) and central autonomic nucleus (CA). SPNs found in the IML had dendrites that projected in various directions. Five types of dendritic projections were noted: medial, rostral, caudal, lateral (including dorsolateral) and ventral. Longitudinal dendritic bundles interconnected each cell cluster in the IML. Medial dendrites of the IML, together with dendrites of the IC and CA, formed transverse dendritic bundles extending from the IML to the central canal. The transverse dendritic bundles disentangled near the midline and formed a loose dendritic plexus in the region just dorsal to the central canal. PVN-fibers labeled with PHA-L were observed primarily in lamina I and intermediate gray (lamina VII). Although varicose PVN-fibers and SPNs coexisted in the IML, the tight packing of the dendritic bundles prevented any clear demonstration of direct contacts between them. On the other hand, PVN-fibers were occasionally found to appose and wind around the primary or secondary dendrites of some SPNs of the CA and IC. These dendrites were studded with varicosities of PVN-fibers for a short length, and terminal boutons of PVN-fibers were also seen to make contact directly with the dendrites. The results of this study substantiated a direct connection between the PVN and SPNs, using a combination of immunohistochemical techniques for PHA-L and CTb. The possible involvement of a direct pathway from the PVN to SPNs in cardiovascular regulation is discussed.Abbreviations AF anterior funiculus - CA central autonomic nucleus - CC central canal - CTb cholera toxin subunit B - HRP horseradish peroxidase - IC nucleus intercalatus - IMf nucleus intermediolateralis pars funicularis - IML nucleus intermediolateralis - IMp nucleus intermediolateralis pars principalis - LDB longitudinal dendritic bundle - LF lateral funiculus - PF posterior funiculus - PHA-L Phaseolus vulgaris leucoagglutinin - PVN hypothalamic paraventricular nucleus - SPNs sympathetic preganglionic neurons - TDB transverse dendritic bundle     

Morpholological analyses of galaninergic inputs to the rat spinal parasympathetic nucleus

We examined the characteristic features of galanin (GAL)-containing nerve afferents in the intermediolateral nucleus (IML) of the rat lumbosacral spinal cord (L6, S1), i.e., spinal parasympathetic nucleus, by immunocytochemistry at both light and electron microscopic levels. Firstly, the types of synapses formed by GAL-immunoreactive (IR) axon terminals and their post- or presynaptic elements were examined in random ultrathin sections. A total of 109 synapses were examined. Axo-dendritic (71%) and axo-somatic (20%) synapses were always of the asymmetrical type. Axo-axonic synapses (9%) were occasionally found; GAL-IR axon terminals were either postsynaptic (3%) or presynaptic (6%) to non-IR axon terminals. By confocal laser microscopy, many GAL-IR axon terminals were seen close to cell bodies and proximal dendrites of the IML neurons that were retrogradely labeled with Fluoro-Gold injected into the pelvic ganglion. Some GAL-IR axon terminals were identified to be presynaptic to them under the electron microscope, by restaining for GAL immunoreactivity with the immunoperoxidase method. These findings suggest that the GAL afferents are involved in the parasympathetic motor regulation of pelvic organs via their central synaptic influences upon preganglionic neurons. Finally, hemi-transection of the upper lumbar segments (L1-L3) or unilateral dorsal rhizotomy (L5-S2) did not significantly alter the immunoreactivity for GAL in the IML. These results suggest that GAL afferents do not originate from regions rostral to the IML nor from the dorsal root ganglion, but probably from GAL cells located at least within the lower lumbar segments and/or sacral spinal cord.     

Oxytocinergic innervation of autonomic nuclei controlling penile erection in the rat.

In the rat, spinal autonomic neurons controlling penile erection receive descending pathways that modulate their activity. The paraventricular nucleus of the hypothalamus contributes oxytocinergic fibers to the dorsal horn and preganglionic sympathetic and parasympathetic cell columns. We used retrograde tracing techniques with pseudorabies virus combined with immunohistochemistry against oxytocin and radioligand binding detection of oxytocinergic receptors to evidence the oxytocinergic innervation of thoracolumbar and lumbosacral spinal neurons controlling penile erection. Spinal neurons labelled with pseudo-rabies virus transsynaptically transported from the corpus cavernosum were present in the intermediolateral cell column and the dorsal gray commissure of the thoracolumbar and lumbosacral spinal cord. Confocal laser scanning microscopic observation of the same preparations revealed close appositions between oxytocinergic varicosities and pseudorabies virus-infected neurons, suggesting strongly the presence of synaptic contacts. Electron microscopy confirmed this hypothesis. Oxytocin binding sites were present in the superficial layers of the dorsal horn, the dorsal gray commissure and the intermediolateral cell column in both the thoracolumbar and lumbosacral segments. In rats, stimulation of the paraventricular nucleus induces penile erection, but the link between the nucleus and penile innervation remains unknown. Our findings support the hypothesis that oxytocin, released by descending paraventriculo-spinal pathways, activates proerectile spinal neurons.     

Somatic noxious mechanical stimulation induces Fos expression in the postsynaptic dorsal column neurons in laminae III and IV of the rat spinal dorsal horn

This study was conducted to ascertain the possible expression of Fos-like immunoreactivity (Fos-LI) in the postsynaptic dorsal column (PSDC) neurons in response to noxious mechanical stimulation of the forepaw glabrous area of normal rats. For this purpose, Fos immunohistochemistry along with Fluoro-Gold (FG) retrograde tracing was utilized. After repeated noxious pinching of the forepaw glabrous area, there was a marked increase in number of Fos-LI neurons in the dorsal horn, including Rexed's laminae III and IV, at C5-T1 spinal cord segments ipsilateral to the stimulation. Between segments C5 and T1, about 40% of the Fos-LI neurons in laminae III and IV were distributed at segment C7. In the rats subjected to the noxious pinch coupled with FG injection into the right cuneate nucleus, PSDC neurons double labeled with Fos and FG were localized in the ipsilateral laminae III and IV extending from segment C5 to T1, with about 70% of them distributed at segments C6 and C7. At segment C6 or C7, double-labeled neurons made up about 10% of the PSDC neurons that projected their axons to the cuneate nucleus. Most of the double-labeled neurons appeared fusiform with their primary dendrites projected dorso-ventrally. The present results suggest that the morphologically distinct, subclasses of PSDC neurons in spinal laminae III and IV may contribute to the central transmission of mechanical nociceptive information through the dorsal column into the cuneate nucleus.     

Localization of NADPH diaphorase, a histochemical marker for nitric oxide synthase, in the mouse spinal cord.

NADPH diaphorase-reactive neurons and fibres are present within the entire spinal cord. Moderately to strongly stained neurons were found in the dorsal horn, in particular in lamina III, as well as around the central canal. A dense accumulation of stained neurons was localized in putative preganglionic sympathetic and parasympathetic nuclei. The somatic motor neurons of the ventral horn were found unlabelled. In view of the recently established identity of NADPH diaphorase with nitric oxide synthase, these results suggest that nitric oxide is involved in sensory and autonomic information processing in the spinal cord.     

猫骶髓“内脏面”L-ENK样神经元的分布和定位投射

应用免疫组织化学和HRP与免疫组织化学双重标记的方法,对骶髓“内脏面”L-ENK样神经元的分布及其与副交感节前神经元和向臂旁外侧核及Barrington核投射的二级传入神经元的关系进行了研究。L-ENK样神经元分布于整个“内脏面”上,尤以中间带外侧核和后连合核为密集。在中间带外侧核内,L-ENK样神经元的分布与向盆神经注入HRP后逆行标记的副交感节前神经元的分布位置重叠,能明显地划分为背侧带和外侧带。在Onuf核及其与骶髓副交感核之间的联系细胞桥上首次发现有L-ENK样神经元存在。将HRP注入盆神经结合L-ENK免疫组织化学反应,在骶髓副交感核外侧带和背侧带均发现大量HRP/L-ENK双标细胞。几乎全部HRP标记细胞均为HRP/L-ENK双标细胞,个别双标细胞出现于中间带外侧核的中间带(interband)内。将HRP注入臂旁外侧核或Barrington核结合L-ENK样免疫组织化学反应,在“内脏面”的中间带外侧核、中介核和后连合核处都发现HRP/L-ENK样双标细胞。上述结果证明猫骶髓“内脏面”、Onuf核及联系细胞桥上均有L-ENK样神经元分布,其中“内脏面”向臂旁外侧核或Barrington核投射的二级神经元有一部分含有L-ENK样活性物质,骶髓副交感核的外侧带、背侧带和中间带均有L-ENK样副交感节前神经元。     

Propriospinal neurons with ascending collaterals to the dorsal medulla,the thalamus and the tectum: a retrograde fluorescent double-labeling study of the cervical cord of the rat

Summary Branching neurons with descending propriospinal collaterals and ascending collaterals to the dorsal medulla, the thalamus and the tectum were studied in the rat's cervical spinal cord (C1–C8), using the retrograde fluorescent double-labeling technique: Diamidino Yellow Dihydrochloride (DY) was injected in the cord at T2, True Blue (TB) was injected in the brain stem. DY-labeled descending propriospinal neurons were present in all laminae, except lamina IX. They were concentrated in lamina I, laminae IV to VIII, and in the lateral spinal nucleus, LSN. TB-labeled neurons projecting to the dorsal medulla were concentrated in lamina IV and the medial parts of laminae V and VI (probably representing postsynaptic dorsal column — PSDC — neurons), but were also present in lamina I, the LSN, the lateral dorsal horn, and in laminae VII and VIII. DY-TB double-labeled neurons giving rise to both a descending propriospinal collateral and an ascending collateral to the dorsal medulla were intermingled with the TB single-labeled neurons. About 4% of the descending propriospinal neurons gave rise to an ascending collateral to the dorsal column nuclei; these double-labeled cells constitute a sizable fraction (10%) of the PSDC neurons. TB-labeled spinothalamic and spinotectal neurons were located in lamina I, the lateral cervical nucleus (LCN), the LSN, the lateral lamina V, lamina VII and VIII, lamina X and in the spinal extensions of the dorsal column nuclei, predominantly contralateral to the TB injections. DY-TB double-labeled neurons were present throughout C1–C8 in the LSN, lateral lamina V, lamina VIII, ventromedial lamina VII, and lamina X. Only very few were observed in lamina I and the LCN, and none in the spinal extensions of the dorsal column nuclei. The double-labeled neurons constituted only a minor fraction of all labeled neurons; 3–5% of the spinothalamic neurons and about 1–7% of the spinotectal neurons were double-labeled. Conversely, only about 1% of the labeled descending propriospinal neurons gave rise to an ascending spinothalamic collateral, and even fewer (0.1 to 0.6%) to a collateral to the dorsal midbrain. The LSN displayed the highest relative content of branching neurons. Up to 20% of its ascending spinothalamic and spinotectal neurons and up to 8% of its descending propriospinal neurons were found to be branching neurons, indicating that the LSN constitutes an unique cell-group in the rat spinal cord.     

Spinal neurons involved in the control of the seminal vesicles: a transsynaptic labeling study using pseudorabies virus in rats

The seminal vesicles are male accessory sex glands that mainly contribute the seminal fluid of the ejaculate. Previous studies have suggested that seminal vesicles are supplied by both sympathetic and parasympathetic nerves. However, this conclusion was mainly based on studies in pelvic major ganglions and direct neuroanatomical evidence of spinal neurons innervating the seminal vesicles is still lacking. In order to map the spinal nerve circuit innervating the seminal vesicles, the present study used the pseudorabies virus (PRV) retrograde tracing technique in combination with immunohistochemistry. Three groups of rats were prepared: (1) nerves intact; (2) right hypogastric nerve and bilateral pelvic nerves sectioned; (3) right pelvic and bilateral hypogastric nerves sectioned. For the intact group, 3 to 5 days after injection of PRV into the left seminal vesicle in male rats, immunohistochemistry for PRV was performed to map the control circuit. Double immunofluorescence experiments against PRV and choline acetyltransferase (ChAT) were performed to discriminate preganglionic neurons and interneurons. Double detection of PRV and galanin (GAL) was also performed to identify lumbar spinothalamic (LSt) cells. Three days after virus injection, both sympathetic and parasympathetic preganglionic neurons were retrograde-labeled. Four days after injection of PRV into the seminal vesicles, PRV-infected neurons were found in the dorsal horn, ventral horn, dorsal gray commissure (DGC), medial gray matter and intermediolateral cell column (IML) from T13 to S1. For the group with an intact hypogastric nerve, 4 days after injection of PRV into the seminal vesicles, PRV-infected neurons were mainly located in DGC and IML of spinal lumbar segments (L) 1-L2. However, in the group with an intact pelvic nerve, PRV-infected neurons were mainly located in DGC of L5-S1 spinal segments. At the L3-L4 level, most of the virus-labeled neurons around the central canal expressed immunoreactivity for GAL, strongly suggesting that they could be LSt cells. These anatomical data support the idea that the sympathetic and parasympathetic nervous system are both involved in the control of the seminal vesicles and we demonstrated a connection between preganglionic neurons innervating the seminal vesicles and LSt cells which play a crucial role in coordinating the spinal control of ejaculation.     

Endogenous lectin (RL‐29) expression of the autonomic preganglionic neurons in the rat spinal cord

Rat spinal neurons expressing lectin RL‐29 are visualized immunohistochemically. RL‐29 immunoreactive (RL‐29 IR) neurons are found in the lateral parts of laminae V‐VII, designated as the intermediolateral cell column (IML) in the thoracic cord, the sacral parasympathetic nucleus (SPN) in the lumbosacral cord, and the dorsomedial nucleus (DMN) of the ventral horn. The majority of RL‐29 IR neurons in the SPN are also labeled by a retrograde tracer DAPI applied to the cut L6‐S1 ventral roots. These data indicate that the majority of RL‐29 IR neurons in the SPN are autonomic preganglionic neurons, thus suggesting that RL‐29 can be a useful tool in marking this subpopulation of neurons. In addition, the presence of previously described RL‐29 IR primary afferent fibers and terminals in the dorsal parts of the cord are confirmed. Anat Rec 254:53–60, 1999. © 1999 Wiley‐Liss, Inc.     

alpha(2a) and alpha(2c) adrenoceptors on spinal neurons controlling penile erection

The thoracolumbar and lumbosacral spinal cord contain respectively sympathetic and parasympathetic preganglionic neurons that supply the organs of the pelvis including the penis. These neurons are influenced by supraspinal information and receive aminergic projections from the brainstem. The presence of the alpha(1)- and alpha(2)-adrenoceptor subtypes has been demonstrated in the rat spinal cord. In this species, we looked for the presence of alpha(2a)- and alpha(2c)-adrenoceptor subtypes in the sympathetic and parasympathetic preganglionic neurons controlling erection. In adult male rats, transsynaptic axonal transport of pseudorabies virus injected into the penis was combined with immunohistochemistry against alpha(2a)- and alpha(2c)-adrenoceptor subtypes. At 4 days survival time, neurons infected with the pseudorabies virus were solely found in the intermediolateral cell column and dorsal gray commissure of segment T12-L2 and in the intermediolateral cell column of segment L6-S1. Neurons and fibers immunoreactive for alpha(2a)- and alpha(2c)-adrenoceptor subtypes were mainly present in the intermediolateral cell column, the dorsal gray commissure and the ventral horn of the T12-L2 and L5-S1 spinal cord, the dorsal horn displayed only immunoreactive fibers. Pseudorabies virus-infected neurons in the autonomic nuclei were both immunoreactive for alpha(2a)- and alpha(2c)-adrenoceptor subtypes and closely apposed by alpha(2a)- and alpha(2c)-immunoreactive fibers.The results suggest an intraspinal modulation of the noradrenergic and adrenergic control of the autonomic outflow to the penis by pre- and postsynaptic alpha(2) adrenoceptors.