Isolation and receptor profiling of ileal enterochromaffin cells.
OBJECTIVE
Enterochromaffin (EC) cells, interspersed throughout the gastrointestinal mucosa, provide most of the serotonin of the body and control intestinal motility, secretion and absorption. We purified EC cells from the rat ileum by a combination of elutriation and density gradient centrifugation in order to characterize the function of this important cell type.


RESULTS
Immunostaining showed that there were 84% serotonin-positive cells in the highly enriched EC fraction as compared with 12% in unfractionated cells, yielding a approximately sevenfold enrichment. Serotonin measurements in the cell suspensions indicated a seven to 14-fold enrichment. Presence of alpha- and beta-adrenoreceptor isoforms, muscarinic M3 and gama-aminobutyric acid (GABA)-A receptors was confirmed by RT-PCR and cytochemistry. Increased expression of VMAT-1 and GABA-A mRNA was also shown by quantitative TaqMan PCR using EC cell RNA. Serotonin release in isolated EC cells was stimulated by noradrenaline, and to a smaller extent, by carbachol, while GABA addition was without effect.


CONCLUSIONS
Our data provide a basis for a new approach to characterize receptors on this unique cell type.
II. Medizinische Klinik und Poliklinik, München, Germany.
A
A
Schäfermeyer
M
M
Gratzl
R
R
Rad
A
A
Dossumbekova
G
G
Sachs
C
C
Prinz
D000818:Animals; D002217:Carbachol / Q000378:metabolism; D002478:Cells, Cultured; D004759:Enterochromaffin Cells / Q000502:physiology*; D005260:Female; D015870:Gene Expression; D007082:Ileum / Q000166:cytology*; D007150:Immunohistochemistry / Q000379:methods; D007413:Intestinal Mucosa / Q000502:physiology; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D043587:Receptor, Muscarinic M3 / Q000032:analysis; D011942:Receptors, Adrenergic, alpha / Q000032:analysis; D011943:Receptors, Adrenergic, beta / Q000032:analysis; D011963:Receptors, GABA-A / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012701:Serotonin / Q000032:analysis; D050492:Vesicular Biogenic Amine Transport Proteins; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D043587:Receptor, Muscarinic M3; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D011963:Receptors, GABA-A; D050492:Vesicular Biogenic Amine Transport Proteins; D012701:Serotonin; D005680:gamma-Aminobutyric Acid; D002217:Carbachol; D009638:Norepinephrine