Mapping of the fluoride resistant acid phosphatase (FRAP) activity in cervico-thoracic-lumbar spinal dorsal horn in rats
- 44 Downloads
The fluoride resistant acid phosphatase (FRAP) is considered a biomarker enzyme of presence and function in nociceptive fibers. Its well described spinal dorsal horn (DH) superficial lamina location contrasts to its less known cervico-lumbar DH distribution. Thus, 15 male Sprague Dawley rats (300–400 g) were anaesthetized (thiopental 60 mg kg−1 i.p.) and laminectomized (C 1-L 5) to extract and fix (formaline 4% + NaF 1%) spinal cords. Cervical, thoracic and lumbar segments were coronally cut (1 mm slices) and micropunched (1 mmØ) at the dorsal horn (both left and right). Samples were diluted in NaF 1% in saline (1000 μL: fragment) and homogenized. Protein concentration of the homogenate was determined by Bradford method to correct variation on tissue sampling and used to compensate enzymatic dilution. FRAP activity was determined by the Gomorri method and expressed as U gr prot−1 L−1. No differences were found between left and right DH FRAP activities (Mann-Whitney U Test, P > 0.05) in any metamera. DH segment values were: cervical 2.53 (2.67–2.40 U gr prot−1 L−1; mean ± 95% CI), thoracic 3.59 (3.96–3.21) and lumbar 2.42 (2.75–2.09). Thoracic FRAP activity was statistically higher (+45.3%) than those from cervical and lumbar DH segments (ANOVA; Ω2 = 0.29; F = 17.78; P = 0.000001; Levene test P = 0.000006). No significant correlation was found among cervicotoraco-lumbar FRAP activity. The increased FRAP activity for thoracic DH could be explained by the thoracic overlapped primary afferents and collateral fibers with cervical or lumbar input added to the basal thoracic FRAP expression.
KeywordsFRAP dorsal horn nociception primary afferent
Unable to display preview. Download preview PDF.
- 1.Bosco, R., Alvarado, S., Quiroz, Daniel, and Eblen-Zajjur, A., Digital cytomorphometry of neurons from de dorsal root ganglion of the rat, J. Histotechnol., 2010, vol. 33, pp. 113–118.Google Scholar
- 6.Jansco, G. and Knyihar, E., Functional linkage between nociception and fluoride-resistant acid phosphatase activity in the Rolando substance, Neurobiology, 1975, vol. 5, pp. 42–43.Google Scholar
- 7.Knyihar, E. and Csillik, B., FRAP: Histochemistry of the primary nociceptive neuron, Progr. Histochem. Cytochem., 1981, vol. 14, pp. 1–137.Google Scholar
- 10.Silverman, J. and Kruger, L., Acid phosphatase as a selective marker for a class of small sensory ganglion cells in several mammals: spinal cord distribution, histochemical properties, and relation to fluoride-resistant acid phosphatase (FRAP) of rodents, Somatosens. Res., 1988, vol. 5, pp. 219–246.PubMedCrossRefGoogle Scholar
- 13.Willis, W. and Coggeshall, R., Sensory Mechanisms of the Spinal Cord: Primary Afferent Neurons and the Spinal Dorsal Horn, New York: Plenum Press, 2004, vol. 1, 3rd ed.Google Scholar
- 15.Brown, A.G., The dorsal horn of the spinal cord, Quart. J. Exp. Physiol., 1982, vol. 67, pp. 193–212.Google Scholar
- 18.Lamotte, C.C., Kapadia, S.E., and Shapiro, Ch.M., Central projections of the sciatic, saphenous, median, and ulnar nerves of the rat demonstrated by transganglionic transport of choleragenoid-HRP (B-HRP) and wheat germ agglutinin-HRP (WGA-HRP), J. Comp. Neurol., 1991, vol. 311, pp. 546–562.PubMedCrossRefGoogle Scholar
- 22.Cadden, S.W., Villanueva, L., Chitour, D., and Le Bars, D., Depression of activities of dorsal horn convergent neurones by propriospinal mechanisms triggered by noxious inputs; comparison with diffuse noxious inhibitory controls (DNIC), Brain Res., 1983, vol. 275, pp. 1–11.PubMedCrossRefGoogle Scholar