Dorsal Neural Sheath Research Articles

Intraoperative Perineural Infiltration of Lidocaine for Acute Postlaminectomy Pain

Prospective, cohort, and clinical study. It was proven that effective control of postoperative pain in lumbar disk surgery improves the patient's recovery. Despite the many advances in surgical and nonsurgical techniques, the most accurate approach in pain relief is still under debate. In this study, our aim was to determine whether neural root blockade before the onset of noxious stimuli could inhibit the production of pain. Forty-five patients undergoing unilateral 1 spinal level (lumbar 5) hemipartial laminectomy were included in the study. In 20 of the patients (group 2), 0.5 mL 2% lidocaine was infiltrated onto the neural root immediately after the exposure; the 25 patients in the control group (group 1) were not injected. All patients were monitored regarding pain determination using a visual analog scale, and the exact time of analgesic requirement during the first postoperative day was noted. Total analgesic dose given during the first postoperative day was also recorded. Perineural lidocaine infiltration extended the early postoperative analgesic period. Although the pain was not completely suppressed, the lidocaine infiltration helped to manage the postoperative pain more effectively. The patients (group 2) who received lidocaine infiltration intraoperatively onto the neural root had a statistically significant longer time before analgesia requested (P<0.001) and also required significantly less analgesic when compared with the control group (P<0.001). For preemptive analgesia for acute postoperative pain in laminectomy surgery, which remains a major concern, we suggest that lidocaine infiltration onto the dorsal neural sheath immediately before retraction of the root may extend the time before analgesia requested and the total analgesic drug consumption.

FMRFamide-like immunoreactivity in the isolated, in vivo cultured ventral ganglion of the fly, Sarcophaga bullata (Parker) (Diptera: Sarcophagidae)

The influence of peripheral connectivity on the survival and differentiation of Phe-Met-Arg-Phe-amide-like immunoreactive (FLI) neurons in the ventral ganglion (VG) of the fly Sarcophaga bullata (Diptera: Sarcophagidae) was examined. Isolated larval VG were cultured in vivo for 13 days. The ganglia had undergone metamorphosis and resembled in situ metamorphosed VG in morphology and in the number and location of FLI neurons. The 3 pairs of large thoracic FLI neurons survived and became translocated to the midventral position extending immunoreactive axons into the dorsal neuropil. The 5 pairs of small FLI neurons also appeared de novo in the abdominal ganglion. However, the dorsal neural sheath of the cultured VG was devoid of FMRFamide-like immunoreactivity that was so characteristic of adult VG, which suggests the importance of peripheral connectivity for the metamorphic modification of FLI neurons.

Immunoreactivity to the antiserum to the mammalian neuropeptide substance P in the central nervous system of the house fly, Musca domestica

Localization of immunoreactivity to the antiserum to the mammalian neuropeptide substance P in the central nervous system of the house fly, Musca domestica, was investigated by immunocytochemical methods. In both the larva and the adult a total of 16 neurons reacted positively against substance P antiserum. Of these, 10 were in the brain and 6 in the thoracic ganglia. The neurons were arranged in bilateral pairs. In the larval nervous system each brain lobe contained a cluster of four pairs of immunoreactive neurons in the dorsal protocerebrum, and the subesophageal ganglion and each of the thoracic neuromeres contained one pair each. The adult nervous system possessed the same number of imunoreactive neurons with identical distribution within the subesophageal and thoracic ganglia. However, the position of the protocerebral neurons was slightly altered. The pattern of immunoreactive axonal processes as well as the very high immunoreactivity observed in the dorsal neural sheath of the adult thoracic ganglion suggest a neurohormonal–neuromodulator role for substance P in this insect.

FMRFamide-like immunoreactivity in the ventral ganglion of the fly sarcophaga bullata: Metamorphic changes

1.Localization of FMRFamide-like immunoreactivity was examined in the ventral ganglion of the fly Sarcophaga bullata using the indirect immunofluorescent method. 2. There are six large cells in the thoracic ganglion which are highly immunoreactive at all stages of development. 3. During metamorphosis the thoracic FLI neurons shift their position from ventrolateral to mid-ventral position and their axons terminate and elaborate a highly immunoreactvie dorsal neutral sheath. 4. It is suggested that the dorsal neural sheath may function as a neurohaemal organ from which FMRFamide-like substances may be released into the haemolymph to act as neurohormones.

Histaminelike immunoreactive neurons innervating putative neurohaemal areas and central neuropil in the thoraco‐abdominal ganglia of the flies Drosophila and Calliphora

The fused thoraco-abdominal ganglia of the flies Calliphora vomitoria and Drosophila melanogaster were investigated immunocytochemically with antisera against histamine. In both insect species, 18 histaminelike immunoreactive (HA-IR) neurons were resolved in these ganglia. Six of these neurons have cell bodies in the thoracic neuromeres and 12 in the fused abdominal neuromeres. All cell bodies are situated ventrally. In Calliphora all cell bodies are arranged in a segmental pattern. In Drosophila only the thoracic cell bodies have a segmental arrangement, whereas the abdominal ones are clustered anteriorly close to the last thoracic neuromere. In both species the six thoracic neurons supply processes to the synaptic neuropil in the thoracic neuromeres and to the dorsal neural sheath. The processes in the neural sheath run anteriorly in the lateral portions of the ganglion into the cervical connective. In a few regions laterally arborizing terminals are found in putative neurohaemal areas. These areas were investigated by electron microscopic immunocytochemistry in Calliphora. The HA-IR terminals (containing small granular vesicles) were found outside the "blood-brain barrier" below the acellular basal lamina of the neural sheath. Release of histamine into the circulation is therefore theoretically possible. The central processes of the six thoracic HA-IR neurons may interact synaptically with large numbers of other neurons in the neuropil, and the peripheral varicose fibers from the same HA-IR neurons possibly are neurohaemal release sites. The abdominal HA-IR neurons, in contrast, form extensive arborizations within the synaptic neuropil only. Both thoracic and abdominal neurons have ipsilateral and contralateral branches as well as processes that invade more than one neuromere. A single HA-IR neuron thus invades large volumes of synaptic neuropil. Histamine may be used by neurons of the ventral ganglia both as neurotransmitter (or neuromodulator) and as a circulating neurohormone released from the neural sheath.

Substance P‐, FMRFamide‐, and gastrin/cholecystokinin‐like immunoreactive neurons in the thoraco‐abdominal ganglia of the flies Drosophila and Calliphora

Immunocytochemical analysis of the thoraco-abdominal ganglia of the flies Drosophila melanogaster and Calliphora vomitoria revealed neurons displaying substance P- (SPLI), FMRFamide-(FLI), and cholecystokinin-like (CCKLI) immunoreactivity. It could be demonstrated that a number of neurons contain peptides reacting with antisera against all the three types of substances, others were either FLI or CCKLI alone. No neurons displayed only SPLI. Instead, the total number (about 30) of SPLI neurons constitute a subpopulation of the FLI/CCKLI neurons. Many of the identifiable immunoreactive neurons seem to be homologous in the two fly species. One set of six large neurons, termed ventral thoracic neurosecretory neurons (VTNCs), are among those that are SPLI, FLI, and CCKLI in both Drosophila and Calliphora. With the present immunocytochemical technique, the detailed morphology of the VTNCs could be resolved. These neurosecretory neurons supply the entire dorsal neural sheath of the thoraco-abdominal ganglia with terminals, thus forming an extensive neurohaemal area. The VTNCs also have processes connecting the thoracic neuromeres to the cephalic suboesophageal ganglion, as well as extensive arborizations in the thoracic ganglia, suggesting an important role in integrating and/or regulating large portions of the central nervous system, in addition to their neurosecretory function. Most of the other SPLI, FLI, and CCKLI neurons in the thoraco-abdominal ganglia seem to be interneurons. However, there are four FLI neurons that appear to be efferents innervating the hindgut and a few abdominal FLI and CCKLI neurons may be additional neurosecretory cells. From the present study it appears as if neuropeptides related to substance P, FMRFamide and CCK have roles as neurotransmitters/neuromodulators and circulating neurohormones in Drosophila and Calliphora.

Distribution and functional significance of Met-enkephalin-Arg6-Phe7-and Met-enkephalin-Arg6-Gly7-Leu8-like peptides in the blowflyCalliphora vomitoria

Neuronal pathways in the retrocerebral complex and thoracico-abdominal ganglionic mass of the blowfly Calliphora vomitoria have been identified immunocytochemically with antisera against the extended-enkephalins, Met-enkephalin-Arg6-Phe7 (Met-7) and Met-enkephalin-Arg6-Gly7-Leu8 (Met-8). Neurons of the hypocerebral ganglion, immunoreactive to Met-8, have axons in the crop duct nerve and terminals in muscles of the crop and its duct. Certain neurons of the hypocerebral ganglion are also immunoreactive to Met-7, and axons from these cells innervate the heart. Met-8 immunoreactive nerve terminals invest the cells of the corpus allatum. The source of this material is believed to be a single pair of lateral neurosecretory cells in the brain. There is no Met-7 immunoreactive material in the corpus allatum. In the corpus cardiacum neither Met-7 nor Met-8 immunoreactivity is present in the cells. However, in the neuropil of the gland certain fibres, with their origins elsewhere, do contain Met-8 immunoreactivity. The most prominent neurons in the thoracic ganglion are the Met-7 immunoreactive ventral thoracic neurosecretory cells, axons from which project to neurohaemal areas in the dorsal neural sheath and also, via the ventral connective, to the brain. Co-localisation studies show that the perikarya of these cells are immunoreactive to antisera raised against several vertebrate-type peptides, such as Met-7, gastrin/cholecystokinin and pancreatic polypeptide. However, their axons and terminals show varying amounts of the peptides, suggesting differential transport and utilisation. Only a few cells in the thoracic ganglion are immunoreactive to Met-8 antisera. These lie close to the nerve bundles supplying the legs. In the abdominal ganglion, Met-8 immunoreactive neurons project to the muscles of the hindgut. This study suggests that the extended enkephalin-like peptides of Calliphora may have a variety of different roles: as neurotransmitter or neuromodulator substances; in the direct innervation of effector organs; and as neurohormones.

Substance P-like immunoreactive neurons in the nervous system of Drosophila

With an antiserum against substance P a small number of neurons could be resolved in great detail in the nervous system of the fruitfly Drosophila melanogaster. In the brain, 10 substance P-like immunoreactive (SPLI) neurons were individually identified. Two of these form extensive bilateral connections with dorsal and ventral protocerebral neuropil. Another two neurons have cell bodies located ventrally in the subesophageal ganglion and processes throughout subesophageal neuropil. In the thoracico-abdominal ganglia 10 SPLI neurons could be identified. Eight of these have large cell bodies located ventrally in thoracic ganglia and two tave small cell bodies located posteriorly in the abdominal ganglia. Six of the 8 thoracic SPLI neurons could be resolved in detail and were found to form: (1) processes in dorsal thoracic and abdominal neuropil as well as processes running through the cervical connective into the subesophageal ganglia; and (2) processes running into the dorsal neural sheath of the thoracic ganglia. The latter processesform an extensive network of varicose terminals over the thoracic ganglia. Our results indicate that a substance P-like neuropeptide can act as a neurohormone released into the circulation from terminals in the neural sheath as well as a neurotransmitter/neuromodulator released by interneurons in the brain.

Substance P-like immunoreactive neurons in the adult nervous system of the fly, sarcophaga bullata

1. The distribution of substance P-like immunoreactivity was investigated in adult CNS of the fieshfly Sarcophaga bullata using peroxidase-antiperoxidase and indirect immunofluorescent methods. 2. Ten cells in the brain and six in the thoracic ganglion exhibited positive immunoreactivity. 3. The dorsal neural sheath of the thoracic ganglion was highly immunoreactive with a large number of varicosities. 4. It is suggested that substance P may function as a neurohormone/neuromodulator in the fleshfly.

Light- and electron-microscopic immunocytochemistry of peptidergic neurons innervating thoracico-abdominal neurohaemal areas in the blowfly.

Ventral thoracic neurosecretory cells (VTNCs) of the blowflies, Calliphora erythrocephala and C. vomitoria, innervating thoracic neuropil and the dorsal neural sheath of the thoracico-abdominal ganglion have been shown to be immunoreactive to a variety of mammalian peptide antisera. In the neural sheath the VTNC terminals form an extensive neurohaemal network that is especially dense over the abdominal ganglia. The same areas are invaded by separate, but overlapping serotonin-immunoreactive (5-HT-IR) projections derived from neuronal cell bodies in the suboesophageal ganglion. Immunocytochemical studies with different antisera, applied to adjacent sections at the light-microscopic level, combined with extensive cross-absorption tests, suggest that the perikarya of the VTNCs contain co-localized peptides related to gastrin/cholecystokinin (CCK), bovine pancreatic polypeptide (PP), Met- and Leu-enkephalin and Met-enk-Arg6-Phe7 (Met-enk-RF). Electron-microscopic immunogold-labeling shows that some of the terminals in the dorsal sheath react with several of the individual peptide antisera, whilst others with similar cytology are non-immunoreactive. In the same region, separate terminals with different cytological characteristics contain 5-HT-IR. Both 5-HT-IR and peptidergic terminals are localized outside the cellular perineurium beneath the acellular permeable sheath adjacent to the haemocoel. Hence, we propose that various bioactive substances may be released from thoracic neurosecretory neurons into the circulating haemolymph to act on peripheral targets. The same neurons may also interact by synaptic or modulatory action in the CNS in different neuropil regions of the thoracic ganglion.

Mapping of enkephalin-related peptides in the nervous system of the blowfly, Calliphora vomitoria, and their co-localization with cholecystokinin (CCK)- and pancreatic polypeptide (PP)-like peptides.

The distribution of enkephalin-like immunoreactive material has been studied in the CNS of C. vomitoria. The presence of both Met- and Leu-enkephalin-related peptides is suggested by differential immunostaining with a variety of antisera. Comparisons made between certain of the enkephalin-immunoreactive perikarya, nerve fibres and terminals with cells in corresponding positions as evidenced in previously published neuroanatomical studies of the dipteran brain have suggested specific enkephalinergic pathways. As examples, one Met-enkephalin-immunoreactive neuron appears to link the lobula with the dorsal protocerebrum, and a group of Leu-enkephalin cells in the pars intercerebralis appear to have arborisations in both the central body (fan-shaped body) and the tritocerebral neuropil around the oesophageal foramen. Neuronal pathways of this type indicate that the enkephalin-like peptides of the fly brain are functioning as neurotransmitters and/or neuromodulators. In the thoracic ganglia, symmetrically arranged cells, immunoreactive to both Met- and Leu-enkephalin antisera, are positioned ventrally in pairs on either side of the mid-line in a sagittal plane. Very little immunoreactive material is observed in the neuropil, however, and the source of the accumulation of Leu-enkephalin-immunoreactivity in the dorsal neural sheath is not certain. It is suggested that this material, in contrast to that present in areas of the brain, acts as a neurohormone and that it may have a physiological role following its release into the haemolymph. The enkephalin-like immunoreactive material of certain neurons identified within the brain and thoracic ganglion shows a complex pattern of co-existence with pancreatic polypeptide- and gastrin/cholecystokinin-like peptides.