Use this URL to cite or link to this record in EThOS: | https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.731890 |
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Title: | Regulation of sperm motility by cell-signalling events in human sperm | ||||||
Author: | Achikanu, Cosmas Ezekaibeya |
ISNI:
0000 0004 6494 6401
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Awarding Body: | University of Birmingham | ||||||
Current Institution: | University of Birmingham | ||||||
Date of Award: | 2017 | ||||||
Availability of Full Text: |
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Abstract: | |||||||
Ca²⁺ signals from activated Ca²⁺ channels (CatSper) and mobilisation of Ca²⁺ stores regulate human sperm cell behaviour as they ascend the female tract. I investigated the effects on human sperm [Ca²⁺]i and behaviour of CatSper channel activation (alkaline pH and progesterone) and Ca²⁺-store mobilisation (4-aminopyridine, thimerosal) using a fluorescence plate reader and CASA. Extracellular alkalinisation raised pH¬i (pHi = 6.9 and 7.2 at pHo7.4 and 8.5 respectively), caused tonic elevation of [Ca²⁺]i, which was partially inhibited by CatSper block and increased the proportion of hyperactivated cells (from 1.8±0.5 to 10.5±1.6%; n=34, P=1x10⁻⁷). Progesterone elevated [Ca²⁺]i but caused negligible hyperactivation. Co-application of these stimuli revealed little, if any, synergistic interaction. Ca²⁺-store mobilisation (4-aminopyridine) caused prolonged [Ca²⁺]i elevation and was associated with strong hyperactivation. Analysis of [Ca²⁺]i and hyperactivation data from 24 different conditions in this study showed a continuous relationship between [Ca²⁺]i and hyperactivation. The strong hyperactivating effect of store mobilisation (compared to CatSper activation) may reflect opening of store-operated channels. Human sperm behaviour assessed over a 180 s recording revealed regular ‘switching’ between progressive and various hyperactivated types. Mobilisation of Ca²⁺ stores potently increased hyperactivated behaviour and suppressed the rate of behavioural switching.
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Supervisor: | Not available | Sponsor: | Federal Government of Nigeria | ||||
Qualification Name: | Thesis (Ph.D.) | Qualification Level: | Doctoral | ||||
EThOS ID: | uk.bl.ethos.731890 | DOI: | Not available | ||||
Keywords: | QH301 Biology | ||||||
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