Journal of anesthesia
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Journal of anesthesia · Sep 1996
Immunocytochemical study of parvalbumin, calbindin D-28k, and calretinin in the superficial dorsal horn of the rat spinal cord following unilateral hindpaw inflammation.
The effect of noxious stimulation on the immunore-activity of the calcium-binding proteins parvalbumin (PV), calbindin-D-28k (CB) and calretinin (CR) was investigated in the superficial dorsal horn of lumbar levels L5-L3 of the rat spinal cord. Freund's adjuvant was injected unilaterally into the hindpaw to induce inflammation. Immunohistochemical techniques were utilized to investigate changes in the calcium-binding proteins 2h and 1, 2, 4, and 7 days after injection. ⋯ After the peak response, at 24h in most animals, there was a decline in the number of responders at 2 days and no differences were noted at 4 days. However, at 7 days, there was again an increase in the number of animals revealing diminished fluorescence intensity in the ipsilateral substantia gelatinosa. Changes in immunoreactivity of calcium binding proteins in the interneurons of the superficial lumbar dorsal horn may reflect hyperactivity within these neurons following noxious stimulation.
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Journal of anesthesia · Sep 1996
Cervical sympathectomy inhibits axonal transport of gonadotropin-releasing hormone during continuous exposure to light in male rats.
To examine the effects of cervical sympathectomy on the transport of gonadotropin-releasing hormone (GnRH) between the hypothalamic neurons and the median eminence, 16 male rats were assigned into four groups: control (C), light (L), light-sympathectomy (LS), and light-colchicine (LC). The C group was kept under a normal circadian rhythm for 2 weeks, and the L group was kept under continuous exposure to light for the same period. The LS group underwent bilateral cervical sympathectomy before being kept under continuous light conditions for 2 weeks. ⋯ The L group showed a decreased number of GnRH neurons, increased concentrations of GnRH fibers and granules, and an increased LH level; however, in the LS and LC groups, these changes were not seen. The response in the LS group resembled that in the LC group. Considering the action of colchicine, which inhibits axonal transport, it is suggested that cervical sympathectomy also inhibits axonal transports of GnRH between the GnRH neurons and the median eminence during continuous exposure to light.
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Journal of anesthesia · Sep 1996
Effects of spinal naloxone and naltrindole on the antinociceptive action of intrathecally administered dexmedetomidine.
Intrathecally administered alpha-2 adrenoceptor and opioid agonists are well known to exert antinociceptive effects in humans and various animals. To examine the interaction of these two groups of agents in the spinal cord, we tested the effect of the opioid antagonists naloxone or naltrindole on the antinociceptive action of an intrathecally administered alpha-2 agonist, dexmedetomidine, using a formalin test in rats. 19 groups of Sprague-Dawley rats (250-300 g) were prepared with chronic intrathecal catheters and examined for the effects of agents on the formalin test. Each group contained 6 animals. 50 μl of 5% formalin was injected subcutaneously in the plantar surface of one hind paw. ⋯ Intrathecal dexmedetomidine (1 μg) maximally depressed the behavioral changes in both phase 1 and phase 2 of the formalin test, which was antagonized by the alpha-2 adrenoceptor selective antagonist atipamezole (0.3 μg). Naloxone (0.1-10 μg) or naltrindole (1-10 μg), when coadministered with dexmedetomidine, showed a dose-dependent antagonism to the effect of dexmedetomidine, whereas naloxone, naltrindole, or atipamezole alone showed no effect on the nocieptive behavior due to formalin injection. These results indicate that the antinociceptive effect of intrathecally administered alpha-2 adrenoceptor agonists may involve opioid receptors in the spinal cord.
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Journal of anesthesia · Sep 1996
Cervical sympathectomy affects adrenocorticotropic hormone and thyroid-stimulating hormone in rats.
To examine the effects of bilateral cervical sympathectomy on the secretion of adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), growth hormone (GH), and prolactin (PRL), 18 male rats were divided into three groups: control (Cont), sham operation (Sham), and bilateral cervical sympathectomy (Symp). All rats were kept under a normal circadian rhythm for 2 weeks. Subsequently, blood was collected and plasma ACTH as well as serum TSH, GH, and PRL levels were measured. ⋯ The present results suggest that cervical sympathectomy in the rat increases ACTH secretion and decreases TSH secretion in the pituitary. These effects seem to be due to a mildly increased secretion of melatonin in the pineal body that probably in turn increases corticotropin-releasing factor (CRF) secretion and decreases thyrotropin-releasing hormone (TRH) secretion in the hypothalamus. Extrapolation of these findings to humans suggests that longterm and repeated stellate ganglion block would affect the pituitary secretions of ACTH and TSH.