Sperm are guided through the female reproductive tract. A temperature difference of about 2°C exists between the storage site and fertilization site of the mammalian oviduct, leading to the hypothesis that sperm can sense and swim towards the oocyte along a rising temperature gradient, known as thermotaxis. Research over the past two decades has reported that sperm feature a sophisticated thermal detection system to detect and track ambient temperature gradients. More recently, thermotaxis is expected to be added to the microfluidic isolation method based on sperm tactic responses for sperm selection. In this article, mammalian sperm thermotaxis is discussed, explaining the underlying behavioural mechanisms and molecular basis, according to the latest research. Finally, this article explores the possible application of sperm thermotaxis in ART.

J. Neurochem. (2012) 122, 582–593. Parkinson’s disease (PD)‐like symptoms and cognitive deficits are inducible by 1‐methyl‐4‐phenyl‐1, 2, 3, 6‐tetrahydropyridine (MPTP). Since cognitive abilities, including memory formations rely also on hippocampus, we set out to clarify the effects of MPTP on hippocampal physiology. We show that bath‐application of MPTP (25 μM) to acute hippocampal slices enhanced AMPA receptor‐mediated field excitatory postsynaptic potentials (AMPAr‐fEPSPs) transiently, whereas N‐methyl‐D‐aspartate (NMDA) receptor‐mediated fEPSPs (NMDAr‐fEPSPs) were facilitated persistently. The MPTP‐mediated transient AMPAr‐fEPSP facilitation was antagonized by the dopamine D2‐like receptor antagonists, eticlopride (1 μM) and sulpiride (1 and 40 μM). In contrast, the persistent enhancement of NMDAr‐fEPSPs was prevented by the dopamine D1‐like receptor antagonist SCH23390 (10 μM). In addition, we show that MPTP decreased paired‐pulse facilitation of fEPSPs and mEPSCs frequency. Regarding activity‐dependent synaptic plasticity, 25 μM MPTP transformed short‐term potentiation (STP) into a long‐term potentiation (LTP) and caused a slow onset potentiation of a non‐tetanized synaptic input after induction of LTP in a second synaptic input. This heterosynaptic slow onset potentiation required activation of dopamine D1‐like and NMDA‐receptors. We conclude that acute MPTP application affects basal synaptic transmission by modulation of presynaptic vesicle release and facilitates NMDAr‐fEPSPs as well as activity‐dependent homo‐ and heterosynaptic plasticity under participation of dopamine receptors.

As a kind of flavonoid, scutellarein is widely used to protect against various human diseases. Although the protective effects of scutellarein have been well studied, its influence on human reproduction remains unknown. In this research, we evaluated the effect of scutellarein on human sperm functions in vitro. Three different concentrations of scutellarein (1, 10, 100 mu M) were applied to ejaculated human sperm. Fertilisation-essential functions, as well as the intracellular calcium concentration ([Ca2+](i)) and protein-tyrosine phosphorylation, two factors which are vital for sperm function regulation, were evaluated. The results demonstrated that all concentrations of scutellarein utilised in this study could significantly increase sperm spontaneous capacitation and acrosome reaction through the enhancement of [Ca2+](i). Besides, the level of tyrosine phosphorylation of sperm could also be increased by scutellarein. Meanwhile, the sperm motility could be improved by 10 and 100 mu M scutellarein, which also make a significant enhancement in sperm penetration ability and hyperactivation. This is one of the limited studies showing the regulation of scutellarein on human spermatozoa functions and is helpful to enrich its application.