Continuous behavioural 'switching' in human spermatozoa and its regulation by Ca2+-mobilising stimuli

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Continuous behavioural 'switching' in human spermatozoa and its regulation by Ca2+-mobilising stimuli. / Achikanu, Cosmas; Correia, Joao; Guidobaldi, HA; Giojalas, LC; Barratt, Christopher L. R.; Da Silva, S M; Publicover, Steve.

In: Molecular Human Reproduction, 13.06.2019.

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Achikanu, Cosmas ; Correia, Joao ; Guidobaldi, HA ; Giojalas, LC ; Barratt, Christopher L. R. ; Da Silva, S M ; Publicover, Steve. / Continuous behavioural 'switching' in human spermatozoa and its regulation by Ca2+-mobilising stimuli. In: Molecular Human Reproduction. 2019.

Bibtex

@article{3646a48abc84482991c5592b7c85e160,
title = "Continuous behavioural 'switching' in human spermatozoa and its regulation by Ca2+-mobilising stimuli",
abstract = "Human sperm show a variety of different behaviours (types of motility) that have different functional roles. Previous reports suggest that sperm may reversibly switch between these behaviours. We have recorded and analysed the behaviour of individual human sperm (180 cells in total), each cell monitored continuously for 3-3.5 min either under control conditions or in the presence of Ca2+-mobilising stimuli. Switching between different behaviours was assessed visually (1 s bins using 4 behaviour categories), and was verified by fractal dimension analysis of sperm head tracks. In the absence of stimuli, approximately 90% of cells showed at least one behavioural transition (mean rate under control conditions = 6.4 ± 0.8 transitions.min-1). Type 1 behaviour (progressive, activated-like motility) was most common but the majority of cells (>70%) displayed at least three behaviour types. Treatment of sperm with Ca2+-mobilising agonists had negligible effects on the rate of switching but increased the time spent in type 2 and type 3 (hyperactivation-like) behaviours (P < 2*10-8; chi square). Treatment with 4-aminopyridine under alkaline conditions (pHo = 8.5), a highly-potent Ca2+-mobilising stimulus, was the most effective in increasing the proportion of type 3 behaviour, biasing switching away from type 1 (P < 0.005) and dramatically extending the duration of type 3 events (P < 10-16). Other stimuli, including 300 nM progesterone and 1% human follicular fluid, had qualitatively similar effects but were less potent. We conclude that human sperm observed in vitro constitutively display a range of behaviours and regulation of motility by [Ca2+]i, at the level of the single cell, is achieved not by causing cells to adopt a 'new' behaviour but by changing the relative contributions of those behaviours.",
keywords = "behaviour, calcium—pH, motility, spermatozoa",
author = "Cosmas Achikanu and Joao Correia and HA Guidobaldi and LC Giojalas and Barratt, {Christopher L. R.} and {Da Silva}, {S M} and Steve Publicover",
year = "2019",
month = jun,
day = "13",
doi = "10.1093/molehr/gaz034",
language = "English",
journal = "Molecular Human Reproduction",
issn = "1360-9947",
publisher = "Oxford University Press",

}

RIS

TY - JOUR

T1 - Continuous behavioural 'switching' in human spermatozoa and its regulation by Ca2+-mobilising stimuli

AU - Achikanu, Cosmas

AU - Correia, Joao

AU - Guidobaldi, HA

AU - Giojalas, LC

AU - Barratt, Christopher L. R.

AU - Da Silva, S M

AU - Publicover, Steve

PY - 2019/6/13

Y1 - 2019/6/13

N2 - Human sperm show a variety of different behaviours (types of motility) that have different functional roles. Previous reports suggest that sperm may reversibly switch between these behaviours. We have recorded and analysed the behaviour of individual human sperm (180 cells in total), each cell monitored continuously for 3-3.5 min either under control conditions or in the presence of Ca2+-mobilising stimuli. Switching between different behaviours was assessed visually (1 s bins using 4 behaviour categories), and was verified by fractal dimension analysis of sperm head tracks. In the absence of stimuli, approximately 90% of cells showed at least one behavioural transition (mean rate under control conditions = 6.4 ± 0.8 transitions.min-1). Type 1 behaviour (progressive, activated-like motility) was most common but the majority of cells (>70%) displayed at least three behaviour types. Treatment of sperm with Ca2+-mobilising agonists had negligible effects on the rate of switching but increased the time spent in type 2 and type 3 (hyperactivation-like) behaviours (P < 2*10-8; chi square). Treatment with 4-aminopyridine under alkaline conditions (pHo = 8.5), a highly-potent Ca2+-mobilising stimulus, was the most effective in increasing the proportion of type 3 behaviour, biasing switching away from type 1 (P < 0.005) and dramatically extending the duration of type 3 events (P < 10-16). Other stimuli, including 300 nM progesterone and 1% human follicular fluid, had qualitatively similar effects but were less potent. We conclude that human sperm observed in vitro constitutively display a range of behaviours and regulation of motility by [Ca2+]i, at the level of the single cell, is achieved not by causing cells to adopt a 'new' behaviour but by changing the relative contributions of those behaviours.

AB - Human sperm show a variety of different behaviours (types of motility) that have different functional roles. Previous reports suggest that sperm may reversibly switch between these behaviours. We have recorded and analysed the behaviour of individual human sperm (180 cells in total), each cell monitored continuously for 3-3.5 min either under control conditions or in the presence of Ca2+-mobilising stimuli. Switching between different behaviours was assessed visually (1 s bins using 4 behaviour categories), and was verified by fractal dimension analysis of sperm head tracks. In the absence of stimuli, approximately 90% of cells showed at least one behavioural transition (mean rate under control conditions = 6.4 ± 0.8 transitions.min-1). Type 1 behaviour (progressive, activated-like motility) was most common but the majority of cells (>70%) displayed at least three behaviour types. Treatment of sperm with Ca2+-mobilising agonists had negligible effects on the rate of switching but increased the time spent in type 2 and type 3 (hyperactivation-like) behaviours (P < 2*10-8; chi square). Treatment with 4-aminopyridine under alkaline conditions (pHo = 8.5), a highly-potent Ca2+-mobilising stimulus, was the most effective in increasing the proportion of type 3 behaviour, biasing switching away from type 1 (P < 0.005) and dramatically extending the duration of type 3 events (P < 10-16). Other stimuli, including 300 nM progesterone and 1% human follicular fluid, had qualitatively similar effects but were less potent. We conclude that human sperm observed in vitro constitutively display a range of behaviours and regulation of motility by [Ca2+]i, at the level of the single cell, is achieved not by causing cells to adopt a 'new' behaviour but by changing the relative contributions of those behaviours.

KW - behaviour

KW - calcium—pH

KW - motility

KW - spermatozoa

U2 - 10.1093/molehr/gaz034

DO - 10.1093/molehr/gaz034

M3 - Article

C2 - 31194869

JO - Molecular Human Reproduction

JF - Molecular Human Reproduction

SN - 1360-9947

M1 - gaz034

ER -