1,721,094 research outputs found
Comparative morphology of “Sturmia-spots” in male tachinids – first results (Diptera: Tachinidae)
No full textThe explosive defensive system of paussine and brachinine bombardier beetles (Coleoptera, Carabidae): comparative morphology and ultrastructure
No full text
PERIPHERAL-NERVE LESIONS CAUSE SIMULTANEOUS ALTERATIONS OF SUBSTANCE-P AND ENKEPHALIN LEVELS IN THE SPINAL-CORD
No full textThe substance P and Met-enkephalin content were measured in the rat lumbar spinal cord after monolateral section of the sciatic nerve. The proximal stump of the lesioned nerve was either ligated, limiting the formation of neuroma, or sutured intraperitoneally, allowing the formation of a very large neuroma. Both types of lesion caused a similar peptide loss. Substance P and Met-enkephalin decreased by about 50% 10 days following the lesion. Such a loss was maintained even 30 days postoperatively and was not affected by the neuroma size. Immunohistochemical stainings showed that the loss of both peptides occurred in laminae I and II of the dorsal horn. It is suggested that pain sensation developing after peripheral nerve lesion may be due to the intraspinal loss of enkephalin rather than to the neuroma formation
High opioid doses inhibit whereas low doses enhance neuritogenesis in PC12 cells
No full textExposure to opiates affects brain development, cell growth as well as in vitro cell differentiation [33,34]. Perinatal treatment with morphine has been reported to impair neuronal plasticity after neonatal lesion with 5,7-dihydroxytryptamine (5,7-DHT) [8]. This study has investigated the use of mu, delta and kappa opioid receptor ligands to examine the selective receptor mediated inhibition of PC12 neurite formation. Morphine and D-Ala(2),D-Leu(5)-enkephalin (DADLE) had a comparable inhibitory potency with a maximal effect at 1 mM concentration, while both naltrexone and naltrindole antagonized their effect at only 10 nM. D-Ala(2)-MePhe(4),Gly-ol(5)-enkephalin (DAMGO) showed only a transient inhibitory effect. The administration of 10 nM guanosine 5'-O-(3-thiotriphosphate) (GTP-gamma-S) prevented morphine inhibition. It is suggested that opiate inhibition of neuritogenesis may be mediated by a receptor with delta-like characteristics coupled to G proteins. On the other hand, the activation of this receptor with morphine at a very low concentration (1 pM) actually enhanced nerve growth factor (NGF) neurite promoting activity
Networking for new politics for areas’ planning and development: the case of Vesuvius area
No full textGlycosaminoglycan-promoted muscle reinnervation and insulin-like growth factor-I levels are affected by anti-growth hormone-releasing hormone exposure
No full textThe present study shows that exposure to antibodies to growth hormone-releasing hormone (GHRH) partially counteracted the promoting effects of treatment with glycosaminoglycans (GAGs) on muscle reinnervation. Sciatic nerve crush was performed in 2-day-old rats, and reinnervation of the extensor digitorum longus muscle was monitored. The extent of reinnervation was rather poor in saline-treated rats, whereas in GAG-treated rats the extent of muscle reinnervation, the recovery of nerve-evoked muscle twitch tension, and the number of motor neurons reinnervating the extensor digitorum longus muscle were greatly enhanced. In addition, treatment with glycosaminoglycans increased markedly insulin-like growth factor-I (IGF-I) levels in denervated muscles. Both types of stimulatory action exerted by GAGs were affected by concomitant exposure to anti-GHRH, with abolition of IGF-I muscle increase and a smaller enhancement in muscle reinnervation. (C) 2001 Wiley-Liss, Inc
Progressive and selective changes in neurotrophic factor expression and substance P axonal transport induced by perinatal diabetes: Protective action of antioxidant treatment
No full textDiabetes-induced embryo malformations and growth retardation are correlated with a variety of biochemical changes including oxidative stress. In this study, we show that the morphological alterations are correlated with progressive and selective changes of mRNA expression in specific neurotrophic factors. At embryological stage E-17, diabetes affected both embryo growth and NGF mRNA expression, which was reduced by as much as 90 and 56% in target tissues of sensory system such as tongue and intestine, respectively. The reduction in retina and heart was around 50%, Conversely, the mRNA expression of low-affinity neurotrophin receptor p75 was increased. At birth, BDNF mRNA expression was affected with a significant generalized reduction,while in vibrissae we observed a reduction of BDNF and p75 mRNAs and an increase of NGF. At postnatal day 14, pups from diabetic mothers showed reduced muscle levels of IGF-I, while we observed a partial impairment of substance P axonal transport at postnatal day 28, Treatment of diabetic mothers with silybin, a flavonoid with antioxidant properties, prevented most of the changes in neurotrophic factor expression and substance P axonal transport with no effects on hyperglycemia and embryo growth retardation. These results indicate that oxidative stress may influence neurotrophic factor synthesis in target territories during development. In addition, these data suggest that nervous system abnormalities observed in diabetic embryopathy may also derive by insufficient neurotrophic factor biosynthesis involving sequentially NGF in the embryo and BDNF and IGF-I in the early postnatal days, Insulin treatment of diabetic mothers normalized hyperglycemia and body growth, with consequent regular embryonic and postnatal development. (C) 1999 Wiley-Liss, Inc
- …
