Abstract
1. The capacity of prostaglandin E2 (PGE2) to enhance the excitatory response elicited by bradykinin in embryonic rat sensory neurones grown in culture was investigated using the whole-cell patch-clamp recording technique. 2. The focal application of bradykinin (BK) produced a small concentration-dependent depolarization that was associated with an inward current and was described by a ligand-binding isotherm having an EC50 of 230 nM. Typically the depolarization was accompanied by action potentials (APs). 3. After pretreatment with 1 microM PGE2 for 10 min, the number of APs elicited by 100 nM BK was increased by about 3-fold. However, PGE2 had no effect on the amplitude of either the BK-elicited depolarization or inward current. The addition of 1 or 10 microM PGE2 had no effect on the resting membrane potential. 4. In all neurones exhibiting PGE2-enhanced excitability, there was a decrease in the amount of injected current necessary to elicit an AP. 5. The enhanced excitability was not due to repeated exposure to BK since neither the amplitude of the BK-evoked depolarization nor the number of APs was altered by the application of BK at 2 min intervals over a period of 30 min. 6. These results are consistent with the notion that PGE2 acts directly on sensory neurones to enhance the response to chemical excitatory agents, like BK, by lowering the AP firing threshold. The PGE2-mediated sensitization does not result from an alteration of the resting potential or modulation of the neuronal response to the chemical agonist.
Full text
PDF







Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Adams P. R., Brown D. A., Constanti A. M-currents and other potassium currents in bullfrog sympathetic neurones. J Physiol. 1982 Sep;330:537–572. doi: 10.1113/jphysiol.1982.sp014357. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Baccaglini P. I., Hogan P. G. Some rat sensory neurons in culture express characteristics of differentiated pain sensory cells. Proc Natl Acad Sci U S A. 1983 Jan;80(2):594–598. doi: 10.1073/pnas.80.2.594. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Burgess G. M., Mullaney I., McNeill M., Dunn P. M., Rang H. P. Second messengers involved in the mechanism of action of bradykinin in sensory neurons in culture. J Neurosci. 1989 Sep;9(9):3314–3325. doi: 10.1523/JNEUROSCI.09-09-03314.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chahl L. A., Iggo A. The effects of bradykinin and prostaglandin E1 on rat cutaneous afferent nerve activity. Br J Pharmacol. 1977 Feb;59(2):343–347. doi: 10.1111/j.1476-5381.1977.tb07498.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Foreman J. C. Peptides and neurogenic inflammation. Br Med Bull. 1987 Apr;43(2):386–400. doi: 10.1093/oxfordjournals.bmb.a072189. [DOI] [PubMed] [Google Scholar]
- Fowler J. C., Greene R., Weinreich D. Two calcium-sensitive spike after-hyperpolarizations in visceral sensory neurones of the rabbit. J Physiol. 1985 Aug;365:59–75. doi: 10.1113/jphysiol.1985.sp015759. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
- Higgs G. A., Moncada S., Vane J. R. Eicosanoids in inflammation. Ann Clin Res. 1984;16(5-6):287–299. [PubMed] [Google Scholar]
- Holzer P. Capsaicin: cellular targets, mechanisms of action, and selectivity for thin sensory neurons. Pharmacol Rev. 1991 Jun;43(2):143–201. [PubMed] [Google Scholar]
- McGehee D. S., Goy M. F., Oxford G. S. Involvement of the nitric oxide-cyclic GMP pathway in the desensitization of bradykinin responses of cultured rat sensory neurons. Neuron. 1992 Aug;9(2):315–324. doi: 10.1016/0896-6273(92)90170-i. [DOI] [PubMed] [Google Scholar]
- Mense S. Sensitization of group IV muscle receptors to bradykinin by 5-hydroxytryptamine and prostaglandin E2. Brain Res. 1981 Nov 23;225(1):95–105. doi: 10.1016/0006-8993(81)90320-6. [DOI] [PubMed] [Google Scholar]
- Naruse K., McGehee D. S., Oxford G. S. Differential responses of Ca-activated K channels to bradykinin in sensory neurons and F-11 cells. Am J Physiol. 1992 Feb;262(2 Pt 1):C453–C460. doi: 10.1152/ajpcell.1992.262.2.C453. [DOI] [PubMed] [Google Scholar]
- Pateromichelakis S., Rood J. P. Prostaglandin E1-induced sensitization of A delta moderate pressure mechanoreceptors. Brain Res. 1982 Jan 28;232(1):89–96. doi: 10.1016/0006-8993(82)90612-6. [DOI] [PubMed] [Google Scholar]
- Piper P. J., Vane J. R. Release of additional factors in anaphylaxis and its antagonism by anti-inflammatory drugs. Nature. 1969 Jul 5;223(5201):29–35. doi: 10.1038/223029a0. [DOI] [PubMed] [Google Scholar]
- Taiwo Y. O., Levine J. D. Indomethacin blocks central nociceptive effects of PGF2 alpha. Brain Res. 1986 May 14;373(1-2):81–84. doi: 10.1016/0006-8993(86)90317-3. [DOI] [PubMed] [Google Scholar]
- Thayer S. A., Perney T. M., Miller R. J. Regulation of calcium homeostasis in sensory neurons by bradykinin. J Neurosci. 1988 Nov;8(11):4089–4097. doi: 10.1523/JNEUROSCI.08-11-04089.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weinreich D., Wonderlin W. F. Inhibition of calcium-dependent spike after-hyperpolarization increases excitability of rabbit visceral sensory neurones. J Physiol. 1987 Dec;394:415–427. doi: 10.1113/jphysiol.1987.sp016878. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Willis A. L. Parallel assay of prostaglandin-like activity in rat inflammatory exudate by means of cascade superfusion. J Pharm Pharmacol. 1969 Feb;21(2):126–128. doi: 10.1111/j.2042-7158.1969.tb08213.x. [DOI] [PubMed] [Google Scholar]
- Yanagisawa M., Otsuka M., García-Arrarás J. E. E-type prostaglandins depolarize primary afferent neurons of the neonatal rat. Neurosci Lett. 1986 Aug 4;68(3):351–355. doi: 10.1016/0304-3940(86)90515-x. [DOI] [PubMed] [Google Scholar]