Dab1 contributes differently to the morphogenesis of the hippocampal subdivisions.

The hippocampal formation (HF) is morphologically and functionally distinguishable into the subdivisions, such as the dentate gyrus (DG), subiculum, and Ammon's horn. The Ammon's horn is further divided into the CA (Cornu Ammonis)1, CA2, and CA3. The Reelin-Dab1 signal is essential for the morphogenesis of the mammalian brain. In the neocortex of Reelin-Dab1 signal mutants the laminar pattern of the neurons is disrupted along the radial axis. Morphological abnormalities in the HF of the Reelin-Dab1 mutants were known, but how these abnormalities appear during development had not been extensively studied. We examined the morphology of the well-developed Dab1 deficient HF by staining with a silver impregnation method in this report, and found that disruption of lamination in the CA1, CA3, and DG was different. Abnormalities observed in the development of Dab1 deficient CA1 were similar to those reported in the neocortical development, while Dab1 deficient CA3 neuronal progenitors radially spreaded beyond presumptive pyramidal layer. The intermediate progenitor cells ectopically located in the Dab1 deficient DG, but neurogenesis was normal in the CA1 and CA3. These observations suggest that the morphogenesis in these HF subdivisions employs different developmental mechanisms involving Dab1 function.

Suppression of Graft Spasm by the Particulate Guanylyl Cyclase Activator in Coronary Bypass Surgery.

BACKGROUND: Spasm of arterial grafts is still a clinical problem in coronary artery bypass surgery. The present study was designed to examine the effect of particulate guanylyl cyclase activator (carperitide) as an antispastic agent in internal thoracic artery and gastroepiploic artery grafts. METHODS: Isolated arterial grafts taken during surgery were studied in organ bath in three ways: the relaxing effect of carperitide on vasoconstrictor-induced precontraction; the inhibitory effect of pretreatment with carperitide on subsequent vasoconstrictor-induced contraction; and the effect of carperitide and nitroglycerin on increase of intracellular cyclic guanosine monophosphate levels. RESULTS: Carperitide produced a concentration-related, endothelium-independent relaxation contracted with potassium chloride, phenylephrine, prostaglandin F2α, or endothelin-1. Carperitide showed significantly higher potency and efficacy than nitroglycerin and nifedipine. Pretreatment with carperitide significantly attenuated the subsequent vasoconstrictor-induced contraction. Carperitide produced more cyclic guanosine monophosphate than nitroglycerin. CONCLUSIONS: Carperitide has a potent inhibitory effect on the vasoconstriction mediated by different vasoconstrictors in human internal thoracic artery and gastroepiploic artery grafts. The use of carperitide in patients during and after coronary artery bypass surgery is favored for the prevention and reversal of graft spasm.

Endothelial dysfunction of internal thoracic artery graft in patients with chronic kidney disease.

OBJECTIVES: The present study was designed to evaluate the association between chronic kidney disease and the endothelial function of internal thoracic artery (ITA) grafts in patients undergoing coronary bypass surgery. An isometric tension study was performed in ITA strips obtained during surgery. Concentration-response curves for acetylcholine (ACh) and sodium nitroprusside were constructed in ITA strips partially precontracted with phenylephrine under the inhibition of cyclooxygenase. The integrity of the endothelium was verified histologically by en-face staining of the luminal surface with the use of silver nitrate solution. RESULTS: In endothelium-intact ITA strips, ACh produced a concentration-dependent relaxation in patients with glomerular filtration rate (GFR, mL/min/1.73 m2) > 60. A concentration-dependent relaxation response also was observed in patients with GFR 30 to 60, but it was reduced significantly compared with those with GFR > 60. In both groups, removal of endothelium or treatment with nitric oxide (NO) synthase inhibitors almost abolished the ACh-induced relaxation. On the other hand, in patients with GFR < 30, mild contraction rather than relaxation was induced at a high concentration of ACh, which was modified neither by treatment with NO synthase inhibitors nor by removal of the endothelium. Vasodilator responses to sodium nitroprusside were comparable among the 3 groups. The relaxation of endothelium-intact strips to a peak ACh concentration correlated positively with GFR. This relationship held true in a multiple linear regression model, and interaction terms between GFR and other risk factors were not statistically significant. CONCLUSIONS: Endothelial function of ITA grafts to release NO is impaired at the time of surgery in patients with chronic kidney disease.

Intact neural system of the portal vein is important for maintaining normal glucose metabolism by regulating glucagon-like peptide-1 and insulin sensitivity.

The portal neural system may have an important role on the regulation of glucose homeostasis since activation of the gut-brain-liver neurocircuit by nutrient sensing in the proximal intestine reduces hepatic glucose production through enhanced liver insulin sensitivity. Although there have been many studies investigating the role of portal neural system, surgical denervation of the sole portal vein has not been reported to date. The aim of this study was to clarify the role of the portal neural system on the regulation of glucose homeostasis and food intake in the physiological condition. Surgical denervation of portal vein (DV) was performed in 10 male 12 week-old Wistar rats. The control was a sham operation (SO). One week after surgery, food intake and body weight were monitored; an oral glucose tolerance test (OGTT) was performed; and glucagon-like peptide-1 (GLP-1) and insulin levels during OGTT were assayed. In addition, insulinogenic index, homeostatic model assessment, and Matsuda index were calculated. All rats regained the preoperative body weight at one week after surgery. There was no significant difference in food intake between DV and SO rats. DV rats exhibited increased blood glucose levels associated with decreased insulin sensitivity but increased GLP-1 and insulin secretion during OGTT. In summary, in the physiological state, loss of the portal neural system leads to decreased insulin sensitivity and increased blood glucose levels but does not affect food intake. These data indicate that an intact portal neural system is important for maintaining normal glucose metabolism.

Distinct localization of peripheral and central types of choline acetyltransferase in the rat cochlea.

We previously discovered a splice variant of choline acetyltransferase (ChAT) mRNA, and designated the variant protein pChAT because of its preferential expression in peripheral neuronal structures. In this study, we examined the immunohistochemical localization of pChAT in rat cochlea and compared the distribution pattern to those of common ChAT (cChAT) and acetylcholinesterase. Some neuronal cell bodies and fibers in the spiral ganglia showed immunoreactivity for pChAT, predominantly the small spiral ganglion cells, indicating outer hair cell type II neurons. In contrast, cChAT- and acetylcholinesterase-positive structures were localized to fibers and not apparent in ganglion cells. After ablation of the cochlear nuclei, many pChAT-positive cochlear nerve fibers became clearly visible, whereas fibers immunopositive for cChAT and acetylcholine esterase disappeared. These results suggested that pChAT and cChAT are localized in different systems of the rat cochlea; pChAT in the afferent and cChAT in the efferent structures.

Ring formation of the internal iliac artery.

We observed an arterial ring communicating the superior and inferior gluteal arteries in the left half of the pelvis of an 88-year-old male. Although many previous studies have shown variations in the internal iliac artery, there has been no literature describing the fenestration. Therapeutic embolization is commonly performed for intractable bleeding in pelvic region. Surgeons should be aware of the arterial ring formation because of possible danger in the intravascular treatments. In patients with similar arterial rings, embolization of the anterior trunk of the internal iliac artery could be insufficient when blood runs through the circle of the arterial ring.

Transfer of bone marrow progenitors prevents coronary insufficiency and systolic dysfunction in the mechanical unloaded heart in mice.

BACKGROUND: Left ventricular-assist device (LVAD) can lead to improvement of cardiac performance in a subset of patients, but chronic mechanical unloading in this fashion may result in left ventricular (LV)-atrophy and impaired functional recovery. Here, we evaluate the efficacy of transferring bone-marrow KSL cells (Lin-/c-kit+/Sca1+), a fraction containing endothelial progenitor cells, for preventing LV-atrophy and malfunction in a mouse model of mechanical unloading of the heart. MATERIALS AND METHODS: Recipients of an isogenic heart transplant received intramyocardial isogenic KSL cells or PBS in three different locations of the left ventricle (LV). Coronary blood flow and LV systolic function were evaluated by echocardiography, and morphologic changes were analyzed on d 7 and 56. RESULTS: PBS-treated mice showed severe systolic dysfunction and large thrombi in LV at both time points. In contrast, KSL cell transfer markedly reduced systolic dysfunction and thrombus size. Furthermore, in comparison with PBS control, KSL recipients had increased coronary blood flow (3-fold, P < 0.01) accompanied by increased LV capillary density and muscle mass. CONCLUSIONS: These results indicate that intramyocardial transfer of bone marrow KSL cells significantly protects against coronary insufficiency and systolic dysfunction in the chronic LV-unloading heart, suggesting that this approach may have clinical potential as a combination therapy with LVAD.

Effect of nitric oxide synthase inhibitor on increase in nasal mucosal blood flow induced by sensory and parasympathetic nerve stimulation in rats.

OBJECTIVES: Neural control of nasal blood flow (NBF) has not been systematically investigated. The aim of the present study was to evaluate the effect of electrical stimulation of both sensory and parasympathetic nerves innervating the nasal mucosal arteries on NBF in rats. METHODS: In anesthetized rats, nasociliary (sensory) nerves and postganglionic (parasympathetic) nerves derived from the right sphenopalatine ganglion were electrically stimulated. We measured NBF with a laser-Doppler flowmeter. RESULTS: The nerve stimulation increased NBF on both sides and increased the mean arterial blood pressure. The increase in NBF was larger on the ipsilateral side than on the contralateral side. Hexamethonium bromide, a ganglion blocker, abolished the stimulation-induced pressure effect and the increase in NBF on the contralateral side, but did not abolish the increase in NBF on the ipsilateral side. The remaining increase in NBF was abolished by N(G)-nitro-L-arginine, a nitric oxide synthase inhibitor. Histochemical analysis with nicotinamide adenine dinucleotide phosphate-diaphorase showed neuronal nitric oxide synthase-containing nerves that innervate nasal mucosal arteries. CONCLUSIONS: Nitric oxide released from parasympathetic nitrergic nerves may contribute to an increase in NBF in rats. The afferent impulses induced by sensory nerve stimulation may lead to an increase in mean arterial blood pressure that is partly responsible for the increase in NBF.

Distribution of a splice variant of choline acetyltransferase in the trigeminal ganglion and brainstem of the rat: comparison with calcitonin gene-related peptide and substance P.

Rat trigeminal ganglion neurons have been shown to contain a splice variant of choline acetyltransferase (pChAT). Here we report the distribution pattern of pChAT-containing afferents from the trigeminal ganglion to the brainstem, compared with that of calcitonin gene-related peptide (CGRP) and substance P (SP), by use of the immunohistochemical techniques in the rat. Most of CGRP(+) SP(+) ganglion cells contain pChAT, whereas half of the pChAT(+) ganglion cells possess neither CGRP nor SP. In the brainstem, pChAT(+) nerve fibers are found exclusively in the trigeminal and solitary systems, although the distribution pattern differs from that of CGRP(+) or SP(+) fibers. First, the ventral portion of the principal sensory nucleus contains many pChAT(+) fibers, with few CGRP(+) or SP(+) fibers. Because this portion receives projections of nociceptive corneal afferents, a subpopulation of pChAT(+) CGRP(-) SP(-) primary afferents is most probably nonpeptidergic nociceptors innervating the cornea. Second, the superficial laminae of the medullary dorsal horn, the main target of nociceptive afferents, contain dense CGRP(+) and SP(+) fibers but sparse pChAT(+) fibers. Because pChAT occurs in most CGRP(+) SP(+) ganglion cells, such sparseness of pChAT(+) fibers implies poor transportation of pChAT to axon branchlets. Another important finding is that pChAT(+) axons are smooth and nonvaricose, whereas CGRP(+) or SP(+) fibers possess numerous varicosities. Our confocal microscopy suggests colocalization of these three markers in the same single axons in some brainstem regions. The difference in morphological appearance, nonvaricose or varicose, appears to reflect the difference in intraaxonal distribution between pChAT and CGRP or SP.

Immunohistochemical detection of L-DOPA-derived dopamine within serotonergic fibers in the striatum and the substantia nigra pars reticulata in Parkinsonian model rats.

On the basis of our previous studies in the normal rat [Arai, R., Karasawa, N., Geffard, M., Nagatsu, I., 1995. L-DOPA is converted to dopamine in serotonergic fibers of the striatum of the rat: a double-labeling immunofluorescence study. Neurosci. Lett. 195, 195-198; Arai, R., Karasawa, N., Nagatsu, I., 1996a. Aromatic L-amino acid decarboxylase is present in serotonergic fibers of the striatum of the rat. A double-labeling immunofluorescence study. Brain Res. 706, 177-179; Arai, R., Karasawa, N., Nagatsu, I., 1996b. Dopamine produced from L-DOPA is degraded by endogenous monoamine oxidase in neurons of the dorsal raphe nucleus of the rat: an immunohistochemical study. Brain Res. 722, 181-184] we have assumed that exogenously administered L-dihydroxyphenylalanine (L-DOPA) is converted into dopamine (DA) in serotonergic (5-HT) fibers within the striatum (ST) and the substantia nigra pars reticulata (SNR). In the present study, an attempt was made to confirm the assumptions in Parkinsonian rats, which were produced by unilateral injections of 6-hydroxydopamine (6-OHDA) into the substantia nigra pars compacta (SNC). The rats exhibiting more than 150 total controversial circles were regarded as satisfactory models of Parkinson disease (PD). Using a dual immunofluorescence histochemistry, we examined DA-immunoreactivity in the 5-HT fibers within the ST and the SNR of the PD model rats after L-DOPA was injected intraperitoneally. In experimental cases with the L-DOPA administration, DA-immunoreactivity was detected in 5-HT fibers in both the ST and the SNR on the 6-OHDA injection side; no DA-immunoreactivity was found in 5-HT fibers in the ST or the SNR in control cases without the L-DOPA administration. The results support the assumption that exogenously administered L-DOPA may be converted into DA within the 5-HT fibers in the ST and SNR of the PD model rats.

Primary sensory neurons containing choline acetyltransferase of the peripheral type in the rat trigeminal ganglion and their relation to neuropeptides-, calbindin- and nitric oxide synthase-containing cells.

We have previously demonstrated that a variant form of choline acetyltransferase (pChAT) is expressed in rat trigeminal neurons. To assess the significance of pChAT in sensory functions, we characterized immunohistochemically pChAT-positive trigeminal neurons in the rat. pChAT-immunoreactivity was observed in a rather uniform pattern in about half of all trigeminal neurons throughout the trigeminal ganglion. The majority of pChAT-positive neurons had small to medium-sized cell bodies. Double immunofluorescent study showed that more than 90% of substance P (SP)-positive trigeminal cells and about 80% of calcitonin gene-related peptide (CGRP)-positive cells exhibited pChAT-immunoreactivity. pChAT-positive cells formed a larger population of neurons than SP-positive or CGRP-positive cells, but they were a different population from calbindin-D(28k)-positive neurons. In addition, pChAT-immunoreactivity was present in a subset of neurons positive for neuronal nitric oxide synthase. The present results suggest that pChAT plays roles not only in nociception, but also in other sensory functions such as mechanoreception mediating tactile sensation.

Demonstration of choline acetyltransferase of a peripheral type in the rat heart.

Cholinergic innervation of the heart has been analyzed using cholinergic markers including acetylcholinesterase, choline acetyltransferase (ChAT), and vesicular acetylcholine transporter (VAChT). In the present study we demonstrate putative cholinergic nerves in the rat heart using an antibody to ChAT of a peripheral type (pChAT), which is the product of a splice variant of ChAT mRNA and preferentially localized to peripheral cholinergic nerves. Expression of mRNAs for pChAT and the conventional form of ChAT (cChAT) were verified in the rat atrium by RT-PCR. Localization of both protein products in the atrium was confirmed by Western blotting. Virtually all neurons and small intensely fluorescent cells in the intrinsic cardiac ganglia were stained immunohistochemically for pChAT. The density of pChAT-positive fibers was very high in the conducting system, high in both atria, the right atrium in particular, and low in the ventricular walls. pChAT and VAChT immunoreactivities were closely associated in some fibers and fiber bundles in the ventricular walls. These results indicate that intrinsic cardiac neurons homogeneously express both pChAT and cChAT. Furthermore, innervation of the ventricular walls by pChAT- and VAChT-positive fibers provides morphological evidence for a significant role of cholinergic mechanisms in ventricular functions.

Mouse brain IgG-like immunoreactivity: strain-specific occurrence in microglia and biochemical identification of IgG.

Unlike the brains of most mammals, the mouse brain appears unique in the massive appearance of cells showing IgG-like immunoreactivity, which has repeatedly been shown via immunohistochemistry. In the present study, we first examined possible species differences in IgG-like immunohistochemical staining in the brains of various rodents, including mice. In four of six mouse strains examined (ICR, Balb/c, C57BL/6, and AKR/J), antibodies against mouse IgG revealed positive staining in many brain microglia. However, no such positive staining was detected in brains of the rat, hamster, guinea pig, or two other mouse strains (CBA/N and CBA/J). We purified IgG-like-immunoreactive molecule(s) biochemically from brain of the ICR mouse as a representative mouse strain. Our amino-acid-sequence analysis proved that the purified protein was identical to serum IgG. The possibility of IgG synthesis by brain microglia in the ICR mouse was denied by our RT-PCR experiments and in situ hybridization histochemistry. In addition, Fcgamma-receptor-deficient double-knockout mice of the C57BL/6 genetic background contained no IgG-immunoreactive microglia in the brain. These results clearly indicate that microglial IgG staining is due to the uptake of serum IgG through Fcgamma receptors. However, the strain-specific mechanisms resulting in microglial IgG uptake remain to be elucidated, in that Fcgamma receptors are omnipresent in microglia of all rodents examined here.

Presence of monoamine oxidase type B protein but absence of associated enzyme activity in neurons within the inferior olive nucleus of the rat.

A previous study demonstrated that monoamine oxidase type B (MAOB) mRNA is located in the inferior olive complex (IO). The purpose of the present study was to examine whether neuronal cell bodies within the IO also express MAOB protein and whether they exhibit associated MAOB enzyme activity. Using immunohistochemistry and enzyme histochemistry, we demonstrated that IO neuronal cell bodies were positive for MAOB immunohistochemistry but negative for MAOB enzyme histochemistry. These findings indicate that IO neuronal cell bodies express MAOB mRNA and produce MAOB protein but curiously do not exhibit MAOB enzyme activity, as might be expected. The mechanism responsible for the failure of MAOB protein to result in enzymatic activity in IO neuronal cell bodies is clearly of significance in terms of functionality but remains to be elucidated.

Rat choline acetyltransferase of the peripheral type differs from that of the common type in intracellular translocation.

Choline acetyltransferase (ChAT), the synthesizing enzyme for acetylcholine, has been implicated to involve multiple isoforms of ChAT mRNA in several animals. Since these isoforms are mostly non-coding splice variants, only a homologous ChAT protein of about 68 kDa has been shown to be produced in vivo. Recent evidence indicates the existence of a protein coding splice variant of ChAT mRNA, which lacks exons 6-9 of the rat ChAT gene. The encoded protein was designated ChAT of a peripheral type (pChAT), because of its preferential expression in the peripheral nervous system as confirmed by Western blot and immunohistochemistry. However, functional significance of pChAT is unknown. To obtain a clue to this question, we examined a possible difference in intracellular trafficking between pChAT and the well-known ChAT of the common type (cChAT) using green fluorescent protein (GFP) in living human embryonic kidney cells. Confocal laser scanning microscopy revealed that pChAT-GFP was detectable in the cytoplasm but not in the nucleus, whereas cChAT-GFP was found in both cytoplasm and nucleus. Following treatment with leptomycin B, a nuclear export pathway inhibitor, pChAT-GFP became detectable in both cytoplasm and nucleus, indicating that pChAT can be translocated to the nucleus. In contrast, the leptomycin B treatment did not seem to affect the content of intranuclear cChAT-GFP. After incubation with protein kinase C inhibitors, enhanced accumulation of pChAT-GFP but not cChAT-GFP occurred in the nucleus. These results clearly indicate that pChAT varies from cChAT in intracellular transportation, probably reflecting the difference in physiological roles between pChAT and cChAT.

Innervation of rat iris by trigeminal and ciliary neurons expressing pChAT, a novel splice variant of choline acetyltransferase.

We have recently discovered a splice variant of choline acetyltransferase (ChAT) mRNA and designated the variant protein pChAT because of its preferential expression in peripheral neuronal structures. In this study, the presence of pChAT in rat iris was examined by immunohistochemistry and Western blot using a pChAT antiserum, in combination with RT-PCR analysis and ChAT enzyme assay. For comparison, the conventional ChAT (cChAT) was studied in parallel. By pChAT immunohistochemistry, intense labeling was found to occur in nerve fibers of the iris and in neurons of the ciliary and trigeminal ganglia. Denervation studies, analyzed by semiquantitative morphometry, indicated that these iridial pChAT fibers originated about half from the ciliary ganglion and the other half from the trigeminal ganglion. The presence of pChAT protein in the iris and trigeminal ganglion was confirmed by Western blot. The expression of pChAT mRNA in the ciliary and trigeminal ganglia was proved by RT-PCR. Although cChAT protein and mRNA were detected in the ciliary ganglion, neither was detectable in the trigeminal ganglion. The contributions of the ciliary and trigeminal ganglia to the iridial ChAT enzyme activity were verified by the present ChAT assay. Here, we provide evidence that iridial pChAT nerves are composed of postganglionic parasympathetic efferents from the ciliary ganglion and, more interestingly, somatic sensory afferents of the trigeminal ophthalmic nerve.

Demonstration of cholinergic ganglion cells in rat retina: expression of an alternative splice variant of choline acetyltransferase.

Acetylcholine acts as a neurotransmitter in the retina. Although previous physiological studies have indicated that some retinal ganglion cells may be cholinergic, several immunohistochemical studies using antibodies to choline acetyltransferase (ChAT) have stained only amacrine cells but not ganglion cells. Recently, we identified a splice variant of ChAT mRNA, lacking exons 6-9, in rat peripheral nervous system. The encoded protein was designated as ChAT of a peripheral type (pChAT), against which an antiserum was raised. In the present study, we examined expression of pChAT in rat retina, both at the protein level by immunohistochemistry using the antiserum and at the mRNA level by RT-PCR. Immunohistochemistry revealed that although no positive neurons were found in untreated intact retinas, many neurons became immunoreactive for pChAT after intravitreal injection of colchicine. Damage of the optic nerve was also effective in disclosing positive cells. Such positive neurons were shown to be ganglion cells by double labeling with a retrograde tracer that had been injected into the contralateral superior colliculus. Western blot analysis and RT-PCR revealed a corresponding band to the pChAT protein and to the amplified pChAT gene fragment, respectively, in retinal samples. In addition, ChAT activity was definitely detected in retinofugal fibers of the optic nerve. These results indicate the presence of cholinergic ganglion cells in rat retina.

Developmental expression of glial cell-line derived neurotrophic factor, neurturin, and their receptor mRNA in the rat urinary bladder.

AIMS: Glial cell-line derived neurotrophic factor (GDNF) and related factors neurturin (NRTN), artemin, and persephin are members of the GDNF family of neurotrophic factors. GDNF and NRTN bind to the tyrosine kinase receptor Ret and the receptors GFRalpha1 and GFRalpha2. The objective was to examine the developmental expression of GDNF, NRTN, and their receptors within the rat urinary bladder. METHODS: Rat bladders dissected from embryonic day (E) 15, postnatal day (P) 0, P14, P28, and adult rats (P60) were investigated by semiquantitative reverse transcriptase polymerase chain reaction. Embryos (E15, E16, and E17) were immunohistochemically stained for neurofilament. RESULTS: GDNF and Ret mRNA levels at E15 were the highest of all the stages we examined and then immediately decreased. In contrast, NRTN mRNA levels did not change between E15 and postnatal day 14; thereafter, they gradually but insignificantly increased. GFRalpha1 and GFRalpha2 mRNA levels were high at E15, after which their signal intensities decreased. In whole-mounted specimens, neurofilament-positive axons were first detected in the bladder at E16. CONCLUSIONS: Our results suggest that GDNF and NRTN may act as trophic factors for neural in-growth to the bladder and/or for the maintenance of mature neurons innervating the bladder. These factors might also be involved in bladder morphogenesis.

Morphologic study of neuronal death, glial activation, and progenitor cell division in the hippocampus of rat models of epilepsy.

PURPOSE: To clarify the relationship of neuronal death to cellular responses, we studied neuronal death as well as reactions of glia and progenitor cells in the hippocampus of two rat models of epilepsy. METHODS: Seizures were induced by either kainic acid (KA) administration or electrical kindling. Neuronal degeneration was assessed by in situ DNA fragmentation analysis. Reactions of glial cells were studied by immunohistochemistry. Progenitor cell division was evaluated using the bromodeoxyuridine (BrdU) labeling method. RESULTS: DNA fragmentation and reactive microglia were observed in the CA1, CA3, and hilus region for 24 h to 4 weeks after KA injection, but not detected in the kindling model. Reactive astrocytes and enhancement of progenitor cell division were seen in both animal models. The number of BrdU-positive cells began to increase on day 3 after KA injection, peaked on day 5, and returned to baseline on day 10. After kindling, the number of BrdU-positive cells began to increase after five consecutive experience of stage I seizures. CONCLUSIONS: These observations show that neuronal degeneration is not necessary for triggering the upregulation. Microglial activation is closely related to the neuronal death process induced by KA.

Expression of neurotrophin messenger RNAs during rat urinary bladder development.

The family of neurotrophins, encompassing nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4/5 (NT-4/5), is important in the regulation of neuronal development and function. We examined the expression of neurotrophin messenger RNAs (mRNAs) in the rat urinary bladder during pre- and postnatal development using competitive reverse transcription-polymerase chain reaction. The mRNA levels showed a biphasic pattern of expression; one peak was at prenatal ages (embryonic day (E)15-E18) and the other peak was at postnatal ages (postnatal day (P)14-P28). NT-4/5, BDNF and NGF mRNA levels were greatest at E15, E16 and E18, respectively. In contrast, NT-3 mRNA levels were significantly highest at P14. These data suggest that neurotrophins are involved in the mechanisms of bladder nerve growth for the prenatal period and reorganization of bladder reflex pathways during the second to the fourth postnatal week.