The alpha7 nicotinic receptors in human fetal brain and spinal cord.
The alpha7 nicotinic acetylcholine receptor subtype is believed to be involved in the regulation of neuronal growth, differentiation and synapse formation during the development of the human brain. In this study the expression of the alpha7 nicotinic acetylcholine receptor was investigated in human fetal brain and spinal cord of 5-11 weeks gestational age. Both the specific binding of [125I]alpha-bungarotoxin to prenatal brain membranes and the expression of alpha7 mRNA were significantly higher in the pons, medulla oblongata, mesencephalon and spinal cord of 9-11 weeks gestational age compared with cerebellum, cortex and subcortical forebrain. A significant positive correlation between gestational age and the expression of alpha7 mRNA was observed in all brain regions except cortex. A positive correlation was also observed between the gestational age and the [125I]alpha-bungarotoxin binding in the pons, medulla oblongata, mesencephalon, and cerebellum. Consequently, a significant relationship between the alpha7 mRNA levels and the binding sites for [125I]alpha-bungarotoxin was found in the fetal brain. The increasing levels of the alpha7 nicotinic acetylcholine receptor during the first trimester support the important role of nAChRs for the development of the central nervous system.
Falk
Lena
L
Department of Clinical Neuroscience, Occupational Therapy and Elderly Care Research, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
Nordberg
Agneta
A
Seiger
Ake
A
Kjaeldgaard
Anders
A
Hellström-Lindahl
Ewa
E
D000199:Actins / Q000235:genetics; D002038:Bungarotoxins / Q000378:metabolism / Q000494:pharmacology; D002490:Central Nervous System / Q000737:chemistry* / Q000196:embryology*; D021983:Cyclophilins / Q000235:genetics; D005333:Fetus / Q000737:chemistry; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D006801:Humans; D007457:Iodine Radioisotopes; D012333:RNA, Messenger / Q000032:analysis; D011869:Radioligand Assay; D011978:Receptors, Nicotinic / Q000032:analysis* / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D064569:alpha7 Nicotinic Acetylcholine Receptor
D000199:Actins; D002038:Bungarotoxins; C579167:Chrna7 protein, human; D007457:Iodine Radioisotopes; D012333:RNA, Messenger; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor; D021983:Cyclophilins