Nociceptive threshold

Proudfit, H. K., and Hammond, D. L. (1981) Alterations in nociceptive threshold and morphine-induced analgesia by intrathecally administered amine antagonists. Brain Res.. 218 393-399. 

Kamel, J., Ohsawa, M., Miyata, S., and Tanaka, S. I. (2008). Preventive effect of L-camosine on changes in the thermal nociceptive threshold in streptozotocin-induced diabetic mice. Eur. J. Pharmacol. 600, 83-86. 

Animal models of nociception can be divided according to the therapeutic indication Acute Pain, Migraine Pain, Inflammatory Pain, Visceral Pain, Neuropathic Pain. Different degrees of chronification (up to weeks in neuropathic pain models) and different stimuli (mechanical, thermal, chemical, electrical) are used depending on the experimental question. In most cases a nociceptive threshold (e g. withdrawal latency of a paw) is determined. Sometimes, nociceptive intensities are determined e.g. in order to quantify hyperalgesia. 

Cravatt et al. (2001) generated mutant mice lacking the faah gene (FAAH / mice) and characterized by altered nociceptive threshold, enhanced memory extinction, and increased sensitivity to the effects of exogenously administered ECs (Cravatt et al., 2001 Varvel et al., 2007). Such behavioral phenotype is compatible with the higher AEA levels measured in these mice (Cravatt et al., 2001). 

Activation of nociceptor PKRs by Bv8 in rats and mice produces nociceptive sensitization to thermal and mechanical stimuli, without inducing any spontaneous, overt nocifensive behavior, or local inflammation. Very low doses of Bv8 (50 fmol) injected into the paw induce a decrease in the nociceptive threshold that reaches the maximum in 1 h and disappears in 2-3 h. The same dose i.th., or higher doses by systemic routes (s.c. and i.v.), induces hyperalgesia with a characteristic biphasic time-course the first peak occurs in 1 h and the second peak invariably in 4—5 h. The first phase depends on a direct action on nociceptors, because it resembles that... 

CRITICAL ASSESSMENT OF THE METHOD The Hot Plate Test is one of the most frequently employed screens for evaluating the nociceptive threshold. It is reliable and reproducible, and remains robust in the face of moderate environmental variations. Most known analgesic substances show... 

In contrast, some data suggest that P2Y receptor agonists can inhibit cytokine release from aetivated spinal cord microglia (Gerevich and Illes, 2004). This process could interrupt chronic pain development and continuation. Thus, UTP and UDP were shown to be analgesic in the neuropathic pain model (Okada et al., 2002). IT pyrimidine nucleotides elevated the nociceptive threshold in the paw pressure and... 

Blakeman KH, Holmberg K, Hao JX, Xu XJ, Kahl U, LendaM U, Baitfai T, Wiesenfeld-HaUin Z, Hokfelt T (2001) Mice over-expressing galanin have elevated heat nociceptive threshold. NeuroReport 12 423-425... 

Charlet A, Lasbennes F, Darbon P, Poisbeau P (2009) Fast non-genomic effects of progesterone-derived neurosteroids on nociceptive thresholds and pain symptoms. Pain 139(3) 603-609... 

Hayes, A.G., Skingle, M., and Tyers, M.B., Effects of single doses of capsaicin on nociceptive threshold in the mdesit. Neuropharmacology, 20, 505-511, 1981. 

To determine the nociceptive threshold of the mice, the hot plate test and the tail flick test were used. Drugs used are dissoved in sterile distilled water from icv administration immediately prior to injection at 5 pl/kg or 5pi mouse, respectively. The icv injection was performed and the site of administration of the peptide was verified in all animals by the injection of 1% methylene blue and the examination of the dye distribution in the cerebral ventricles at the termination of the experiment. To evaluate the hot plate and tail flick test responses detailed below, a control latency (To) was obtained from the mean of two latencies determined prior to drug injection test latencies (T1) were determined at various times after injection for each animal. The percentage of analgesia was calculated as (Ti -To)/ (T2 -To) x 100 where the cut off times (T2) for the hot plate and tail flick test were 60 and 15s, respectively. The median antinociceptive dose (ED50) and 95% confidence limits were calculated according to the method of Litchfield and Wilcox. 

Amann, R., Schuligoi, R., Herzeg, G. and Donnerer, J. (1996) Intraplantar injection of nerve growth factor into the rat hind paw local edema and effects on thermal nociceptive threshold. Pain 64 323-329. 

Effect on nociceptive thresholds Chemical Mechanical Thermal... 

Holzer, P., Jurna, I., Gamse, R., and Lembeck, F., 1979, Nociceptive thresholds after neonatal capsaicin treatment, Eur.j. Pharmacol. 58 511-514. 

Paalzow GHM, Paalzow LK 1983 Yohimbine both increases and decreases nociceptive thresholds in rats Evaluation of the dose-response relationship. Naunyn-Schmiedebergs Arch Exp Pathol Pharmakol 322 193-197... 

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