Central 5-HT containing pathways have been shown to play an important role in the control of micturition with a focus on 5-HT receptor influence on the parasympathetic outflow to the bladder, and somatic outflow to the external urethral sphincter (EUS) in the rat. 5-HTjA and 5-HT7 receptors have been revealed to be physiologically involved in the control of micturition. Moreover, from the literature, activation of the 5-HT2 receptor, specifically 5-HT2C receptor has been observed to be inhibitory on the micturition reflex, although no physiological role for this receptor subtype has yet been established. Using reportedly selective 5-HT2 receptor agonists and antagonists, the present work reveals the excitatory actions of the 5-HT2A receptor on the external urethral sphincter and the micturition reflex, the inhibitory actions of the 5-HT2C receptor in micturition and the involvement of 5-HT2B receptors in mediating urethral smooth muscle contraction. Further, data from the present study demonstrates that 5-HT2A receptors excite the external urethral sphincter at the level of the sacral spinal cord and further supports the view that the inhibitory action of the 5-HT2C receptors on micturition is centrally mediated. Molecular evidence regarding expression of 5-HT2 receptor subtypes in the lower urinary tract of the rat is also provided in the present study, with 5-HT2A, 5- HT2B and 5-HT2C receptor mRNA expression observed in the rat bladder, urethra and brain respectively. Overall, this thesis provides evidence for the involvement of 5-HT2 receptors in the control of micturition, although it is still unclear as to the physiological role of this receptor family in the control of micturition.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:498880 |
| Date | January 2008 |
| Creators | Mbaki, Yvonne |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1444814/ |
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