Identification of glutamate receptors and transporters in mouse and human sperm.
gamma-Aminobutyric acid (GABA) and glutamate (Glu) are considered as the predominant inhibitory and excitatory neurotransmitters in mammalian central nervous systems (CNS), respectively. The presence of the GABA system and metabotropic glutamate receptors in sperm prompted us to explore the existence of ionotropic glutamate receptors and glutamate transporters in sperm. Immunofluorescent analysis was used to investigate the existence and location of glutamate, glutamate receptor (NR2B), and glutamate transporter (GLT1) in mouse and human sperm. Our present results showed that NR2B was located in the midpiece of sperm, whereas GLT1 mainly existed in the head. Moreover, glutamate uptake activity was detected in mouse sperm and it could be blocked by dihydrokainic acid (DHK, GLT1-selective inhibitor) and DL-threo-beta-hydroxyaspartic acid (THA, nonselective inhibitor). In addition, reverse transcription-polymerase chain reaction technique and sequencing analysis revealed that glutamate transporters (GLT1 and EAAC1) and ionotropic glutamate receptors (NR1, NR2B, GluR6, and KA2) existed in mouse sperm as well as in human sperm. The present findings are the first direct evidence for the existence of ionotropic glutamate receptors and glutamate transporters in sperm. It also indicates that, in sperm, glutamate receptors and transporters might have functions other than neurotransmission.
Hu
Jia Hua
JH
Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, Peoples' Republic of China.
Yang
Na
N
Ma
Ying Hua
YH
Jiang
Jie
J
Zhang
Jin Fu
JF
Fei
Jian
J
Guo
Li He
LH
D027322:Amino Acid Transport System X-AG / Q000235:genetics / Q000378:metabolism; D000818:Animals; D027342:Excitatory Amino Acid Transporter 2 / Q000235:genetics* / Q000378:metabolism*; D050580:Excitatory Amino Acid Transporter 3; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D050491:Glutamate Plasma Membrane Transport Proteins; D018698:Glutamic Acid / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018092:Kainic Acid Receptors / Q000235:genetics / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics* / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013094:Spermatozoa / Q000502:physiology*; D027981:Symporters / Q000235:genetics / Q000378:metabolism; D014316:Tritium; D000097806:GluK2 Kainate Receptor
D027322:Amino Acid Transport System X-AG; D027342:Excitatory Amino Acid Transporter 2; D050580:Excitatory Amino Acid Transporter 3; D050491:Glutamate Plasma Membrane Transport Proteins; D018698:Glutamic Acid; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate; D027981:Symporters; D014316:Tritium; D000097806:GluK2 Kainate Receptor; C409466:NR1 NMDA receptor; C121001:NR2B NMDA receptor; C493400:SLC1A1 protein, human; C493399:Slc1a1 protein, mouse