Neuroscience letters
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Neuroscience letters · Aug 2002
Auditory sensory memory for random waveforms in the Mongolian gerbil.
Mongolian gerbils (N = 21) were trained to discriminate between continuous and repeated auditory white noise. While for periods up to 40 ms of the repeated noise spectral effects make this a perceptual task, longer periods require auditory sensory memory to solve the task. ⋯ By long-term training (156 days) using an optimized training paradigm two further gerbils learned to discriminate up to a period length of 360 ms but could not proceed at 400 ms. While this falls short of human performance, it demonstrates for the first time sensory memory for random waveforms in animals.
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Neuroscience letters · Aug 2002
Event-related skin conductance responses to musical emotions in humans.
While the reasons underlying musical emotions are unclear, music is nevertheless a powerful elicitor of emotion, and as such, may induce autonomic nervous system responses. One typical measure of this neural pathway is the skin conductance response (SCR). This response generally depends upon stimulus arousal, one of the two motivational determinants of emotion. ⋯ In addition, subjects' ratings of the emotional clarity for each excerpt did not parallel the corresponding SCRs magnitudes. The results show that SCRs can be evoked and modulated by musical emotional arousal, but are not sensitive to emotional clarity. While several studies have been performed with visual scenes and environmental sounds, the present study brings similar evidence from the musical domain.
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Neuroscience letters · Aug 2002
Involvement of adenosine in the anti-allodynic effect of amitriptyline in streptozotocin-induced diabetic rats.
Recent observations suggest the involvement of adenosine in the peripheral antinociceptive effect of amitriptyline in nerve-injury-induced neuropathic pain. The aim of the present investigation was to evaluate, firstly, the peripheral and systemic effects of amitriptyline on tactile allodynia in the streptozotocin (STZ)-induced diabetic rat model of neuropathic pain and, secondly, whether caffeine coadministration affects the actions of amitriptyline. Diabetes was induced by a single intraperitoneal (i.p.) injection of STZ (50 mg/kg), and tactile allodynia was detected by application of von Frey filaments to the ventral surface of the hindpaw. ⋯ Coadministration of caffeine (5 mg/kg, i.p.; 1500 nmol, s.c.), at doses which produced no effect on its own, partially reversed systemic and local anti-allodynic effects of amitriptyline. These results indicate an anti-allodynic effect of both peripheral and systemic amitriptyline, and suggest the involvement of endogenous adenosine in the action of amitriptyline in this rat model of painful diabetic neuropathy. These data also suggest that topical application of tricyclic antidepressants may be useful in treating neuropathic pain in diabetics.
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Neuroscience letters · Aug 2002
Nerve growth factor induces systemic hyperalgesia after thoracic burn injury in the rat.
Acute burn injury is usually associated with pain in the injured and nearby areas. However, we have recently reported that a thoracic scald induces hindpaw hyperalgesia during the healing stage in rats. ⋯ The concentration of nerve growth factor (NGF) in the skin of the chest increased markedly during the healing stage. Moreover, rats injected daily with anti-NGF serum after burn injury did not develop hyperalgesia, suggesting that increased NGF in the tissue of the healing skin is a key factor causing systemic hyperalgesia during the recovery stage.
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Neuroscience letters · Aug 2002
Inhibitory effects of intrathecally administered interleukin-1beta on carrageenan-induced hyperalgesia and spinal c-Fos expression in rats.
The present study investigated the effects of interleukin-1beta (IL-1beta) injected intrathecally (i.t.) on carrageenan-induced thermal hyperalgesia and spinal c-Fos expression. The paw withdrawal latency (PWL) by the thermal stimulus was taken as an index of the thermal hyperalgesia of rats. I.t. injection of 10 ng IL-1beta significantly increased the PWL of the carrageenan-injected paw. ⋯ Three hours after i.pl. injection of carrageenan, the number of c-Fos-like immunoreactive (c-Fos-LI) neurons was significantly increased in laminae I-II, III-IV and V-VI of the ipsilateral spinal cord at L4-5 with the higher density in laminae I-II and V-VI. I.t. pre-injected IL-1beta significantly decreased the number of carrageenan-induced c-Fos-LI neurons in laminae I-II in the ipsilateral spinal cord and also inhibited the hyperalgesia induced by i.pl. carrageenan. These results suggested that i.t. injection of IL-1beta suppressed the central nociceptive input into laminae I-II and produced an antinociceptive effect.