Reproduction Abstracts

Ca2+ signaling is crucial for regulation of sperm motility and [Ca2+]i oscillations may underlie ‘switching’ of sperm behaviors in human spermatozoa, which is believed to be important for sperm progression in the female tract. We have investigated the contribution of membrane potential (Vm) and the sperm Ca2+ channel CatSper to [Ca2+]i oscillations induced by progesterone (P4). Manipulation of Vm was p...

CatSper channels are expressed specifically in the principal piece of the sperm flagellum. In human sperm Catsper channel activation is polymodal and sensitive to increased pHi, progesterone and other agonists, potentially resulting in synergistic enhancement of Ca2+ influx and hyperactivation (1) We have investigated if the interaction of pHi with the CatSper agonist progesterone and 4-aminopyridine (4AP), a potent activator of hyperactivation in human sperm. [Ca<s...

Human sperm use different behaviours for different aspects of sperm transport and fertilisation. We have investigated the effects of preparation method (density gradient method and direct swim-up) on sperm behaviour and manipulated Ca2+ signalling (the primary regulator of sperm motility) to induce different behaviours and assessed their effects on penetration of human sperm through viscous medium (methylcellulose).Cells prepared by swim-up pe...

Catsper is a Ca2+ permeable ion channel in the principal piece of the sperm flagellum that is crucial in regulation of motility. It is multimodally sensitive, being activated by voltage, pHi and diverse agonists including progesterone. Elevation of pHi and progesterone both shift voltage-sensitivity of the channel to more negative potentials and thus may act synergistically to enhance Ca2+-influx.1 However, intracellular alkalinisation of human...

Ca2+ signalling is critical for regulation of sperm motility. [Ca2+]i oscillations, which may underlie observed ‘switching’ of sperm behaviors, occur in human spermatozoa stimulated with progesterone. Our work aimed to investigate the potential contribution of changes in membrane potential, leading to cyclical activation of voltage dependent Ca2+-influx pathways, to [Ca2+]i oscillations. Spermatozoa we...

Introduction: Potassium channels are essential for the physiological regulation of cell excitability through control of membrane hyperpolarisation. In human sperm slo1 and/or 3 have been proposed to mediate this function (Mannowetz et al. 2013, Mansell et al. 2014). However, to date there is no information on dysfunction in men and the consequence of this for their fertility.Materials and methods: Men undergoing ICSI treatment or recall...