摘要:

THE effect of 4 weeks of hind limb immobilization on nicotinic acetylcholinergic receptors (nAChRs) in the neuromuscular junction of the soleus (SOL) and tibialis anterior (TIB) muscles was studied in rats. Quantitative measurements of the receptors was performed using [3H]α-bungarotoxin ([3H]α-BTx) receptor autoradiography. Junctional and extrajunctional nAChRs were significantly increased in the SOL and TIB after 4 weeks immobilization. However, a significant decrease in fiber cross-sectional area was observed only in the SOL muscle. Remobilization for 4 weeks reversed the changes in cholinergic receptors and muscle fibers but not in bone. Our findings suggested that lack of nerve impulses are of importance for the events that take place after immobilization leading to muscle atrophy and osteoporosis.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

STATHMIN is a cytosolic protein expressed particularly in the developing nervous system, whose phosphorylation is correlated with the action of multiple extracellular stimuli regulating cell proliferation and differentiation. In this study, we used an antibody that specifically recognizes the carboxyterminal region of stathmin to analyze the distribution of this protein in the olfactory system of adult rats, and found a high and selective immunoreactivity in immature olfactory receptors of the olfactory neuroepithelium and in cells of the rostral migratory stream. These results reveal an expression of stathmin in regions of the adult nervous system characterized by striking structural plasticity and cell renewal, suggesting that this protein could play a role in the differentiation of newly generated cell populations.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

PERINATAL choline supplementation can improve performance on a variety of spatial memory tasks in adulthood. In order to extend these studies, we have investigated the effects of perinatal choline supplementation on the performance of a peak-interval timing task in which a 20 s temporal criterion was trained for a visual signal in adult (3–6 months old) rats. Following 5 weeks of baseline training, rats received systemic injections of nicotine (0.1, 0.2, or 0.4 mg/kg, s.c.) or saline prior to testing on the peak-interval timing task. The results indicated that perinatal choline supplementation increased rats' sensitivity to the 20 s temporal criterion during baseline training and facilitated the clock speed enhancing effects of nicotine during drug testing. The present study extends the types of long-term cognitive enhancement produced by perinatal choline supplementation to include the temporal processing domain and relates these effects to modifications in cholinergic function.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

TRANSECTION of a peripheral nerve in neonatal rats induces an extensive death of axotomized neurons. We demonstrate here that spinal motoneurons and sensory dorsal root ganglia neurons become TUNEL-labeled after sciatic nerve transection in neonatal rats, thus indicating that apoptotic mechanisms are involved in the death process. Interestingly, there is also a profound increase of TUNEL-labeled interneurons in the deep dorsal horn. This location suggests that an intact afferent imput and/or contact with target cells is essential for interneuronal survival. Death of motoneurons and sensory neurons could be a result of the injury per se and/or the deprivation of neurotrophic substances, secondary to the loss of contact with target cells.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

THE effects of topical application of interleukin-6 (IL-6) on the short and long latency evoked unit responses of the neurones in the primary somatosensory (SI) cortex were determined quantitatively in anaesthetized rats. IL6 (0.01, 0.1, 1.0 units) significantly suppressed (−15.13 ± 3.4%) short latency afferent sensory responses, while it induced profound facilitation (+464.74 ± 132.7%) of long latency responses in a dose-dependent manner. IL-6induced afferent modulations fully recovered by 60 min after drug administration. In control experiments, saline solution containing 0.2% bovine serum albumin, used as a vehicle, did not affect afferent sensory transmission. Implications of these results are discussed with reference to the different somatosensory functions of short and long latency response components in the SI cortex.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

A polyclonal goat antiserum against the C-terminal end of the rat vesicular acetylcholine transporter (VAChT) was used to examine the postnatal expression of this protein in the rat retina. The transporter protein was localized in choline acetyltransferase (ChAT)-positive, cholinergic interneurones (so-called starburst amacrine cells) in the inner retina. During postnatal development the VAChT was expressed from postnatal day 1 onward by the two subsets of these cholinergic amacrine cells. The immunocytochemical detection of the VAChT provides a specific marker for the study of developing cholinergic neurones in the rat retina, which so far has only been monitored by ChAT immunoreactivity in the second postnatal week.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

NF-κB is a nuclear transcription factor involved in the control of numerous cellular functions, particularly regulation of survival. Translocation from the cytoplasm to the nucleus, an event essential for NK-κB activation, could be mediated through the low-affinity nerve growth factor receptor, p75, which has recently been shown to mediate cell death. In the human brain, p75 is exclusively expressed in cholinergic neurons of the basal forebrain. This population degenerates in Alzheimer's disease (AD). To investigate whether p75 could play a role in the vulnerability of these neurons via NF-κB activation, we studied the cellular distribution of NF-κB in the nucleus basalis of Meynert of four AD patients and four control subjects. The immunostaining observed both in AD patients and control subjects was limited to large, probably cholinergic, neurons. In AD, the proportion of neurons with nuclear NF-κB staining was significantly increased, suggesting an association between NF-κB functions and the process of cholinergic degeneration in AD.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

IT has been suggested that Mozart's music may have beneficial effects on the performance of cognitive tasks in humans. In the present study the effects of Mozart's piano music, white noise, simple rhythm and silence were studied on the performance of a delayed response (DR) task in monkeys. The acoustic treatments were given for 15 min, either before or during DR testing. The acoustic treatments did not affect DR performance when given before testing. However, Mozart's piano music played during DR testing caused a significant deterioration in the performance of the monkeys, whereas white noise improved it. It is suggested that Mozart's music serves as distractive stimulation during DR performance thus affecting working-memory-related neuronal processing and performance. White background noise, on the other hand, may improve DR performance by protecting against environmental distraction during testing.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

ALTHOUGH considered as an intestinal motor stimulant, substance P can inhibit intestinal peristalsis via stimulation of tachykinin NK1receptors. Since NK1receptors are present on enteric nitrergic neurones, the contribution of nitric oxide (NO) to the peristaltic motor inhibition caused by tachykinins was examined in luminally perfused segments of isolated guinea-pig ileum. Substance P (100 nM) and the NK1receptor agonist substance P methyl ester (100 nM) increased the intraluminal pressure threshold at which peristaltic contractions were elicited. This inhibitory influence on peristalsis was prevented by the NO synthase inhibitor NG-nitro L-arginine methyl ester (300 μM) in an enantiomerselective manner. It is concluded that the substance P/NK1receptor-mediated depression of intestinal peristalsis involves inhibitory motor pathways utilizing NO as a transmitter.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

WE have evaluated the G1H line of transgenic mice overexpressing a familial ALS mutation of SOD1 (Gly93→Ala) in tasks assessing different aspects of motor function to determine how early these deficits could be detected and their order of appearance. The earliest deficits were observed in tests of muscle strength and coordination as early as 8 weeks of age and their development appeared to be biphasic, whereas spontaneous activity was not impaired until 15 weeks of age. These studies show that, in addition to the previously demonstrated histological and electromyographic deficits, this transgenic mouse also presents changes in motor function reminiscent of the human disease, reinforcing and extending its validity as an animal model of familial amyotrophic lateral sclerosis (FALS) and allowing the investigation of novel drug treatment for ALS.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID