Neuroscience letters
-
Neuroscience letters · Jan 1990
Somatotopical arrangement of rat spinal dorsal horn cells processing input from deep tissues.
Extracellular recordings were made from 29 dorsal horn neurones which could be driven by mechanical stimulation of deep tissues, in spinal segment L4 of rats. The recording sites were marked by iontophoresis of pontamine sky blue. ⋯ The deep cells showed a correlation between the recording sites in the dorsal horn and the location of the receptive fields on the hind-limb: the more distal a deep receptive field was situated on the hind-limb the more medial was the location of the recording site in the dorsal horn. In cutaneo-deep neurones the correlation was statistically significant for the deep receptive fields but not for the cutaneous ones.
-
Neuroscience letters · Jun 1989
B-vitamins potentiate the antinociceptive effect of diclofenac in carrageenin-induced hyperalgesia in the rat tail pressure test.
B-vitamins possess antinociceptive and antiinflammatory activity. The rat tail pressure test was used to examine whether a mixture of the vitamins B1, B6, and B12, clinically used as Neurobion, has antinociceptive activity itself or potentiates the effect of the non-steroidal antiinflammatory drug (NSAID) diclofenac on carrageenin-induced hyperalgesia. ⋯ Nevertheless, lower doses which alone were lacking in activity (100-250 mg/kg B1 and B6, 1-2.5 mg/kg B12 p.o.) dose-dependently potentiated the antinociceptive of diclofenac. This result supports the clinical experience of a reduced need for diclofenac when B-vitamins are administered concomitantly.
-
Neuroscience letters · Apr 1989
Chronic amitriptyline decreases autotomy following dorsal rhizotomy in rats.
In the rat, unilateral dorsal cervicothoracic rhizotomy (C5-T1), a proposed model of chronic pain, resulted in autotomy of the ipsilateral limb. The self-mutilation lesions were evaluated daily by means of an autotomy score from the 1st to the 80th postoperatory day. ⋯ A more pronounced effect was observed with the lowest dose of amitriptyline suggesting the existence of a therapeutic window. Possible mechanisms for the antinociceptive effect of amitriptyline in this model are discussed.
-
In unilaterally vagotomized rabbits, changes in single vagal nerve fibers from the lung stretch and irritant receptors were studied during the cough reflex following ammonia vapour administered into the lungs. The discharge rates of slowly adapting pulmonary stretch receptors (SARs) before the onset of cough and at the onset of cough did not change significantly. In contrast, the occurrence of cough after ammonia inhalation was usually preceded by vigorous stimulation of the rapidly adapting pulmonary stretch receptors (RARs). These results suggest that the genesis of cough provoked by ammonia is mainly mediated by afferent input from RARs.
-
Neuroscience letters · Feb 1988
Properties of A delta high threshold mechanoreceptors in the rat hairy and glabrous skin and their response to heat.
Forty-three high threshold mechanoreceptors (HTMs) with myelinated fibres were characterized in hairy and glabrous skin of the hind limb of the rat. Mechanical thresholds and conduction velocities were similar in both skin areas. ⋯ A delta-HTMs in rat skin, either hairy or glabrous, are thus much less easily excited by heat than are similar units in rabbit, cat or monkey skin. C-fibres in rat skin are known to respond well to heating, and therefore provide the only significant input about noxious heat in this species.