Evidence for microvesicular storage and release of glycine in rodent pinealocytes.
Prompted by previous studies suggesting a regulatory role for the inhibitory amino acid gamma-aminobutyric acid (GABA) within the mammalian pineal gland, we carried out a study of rat and gerbil pineal organs to elucidate whether there is evidence for a vesicular storage and release of GABA and/or glycine. Immunohistochemistry revealed the presence of the vesicular inhibitory amino acid transporter in pinealocytes. Moreover, we found that, in addition to glutamate and aspartate, cultured pinealocytes also released glycine upon stimulation by depolarizing concentrations of KCl, whereas the content of GABA in the culture medium did not exceed the detection limit either under control conditions or following KCl application. Therefore, we propose that glycine is a further component of the paracrine signaling system within the pineal organ which is based on the compartment of synaptic-like microvesicles (SLMVs) inside pinealocytes.
Redecker
P
P
Medizinische Hochschule Hannover, Abt. Anatomie 1, Carl-Neuberg-Strasse 1, D-30625 Hannover, Germany. redecker.peter@mh-hannover.de
Pabst
H
H
Löscher
W
W
Steinlechner
S
S
D026905:Amino Acid Transport Systems; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D005849:Gerbillinae; D018698:Glutamic Acid / Q000378:metabolism; D005998:Glycine / Q000378:metabolism*; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D010870:Pineal Gland / Q000378:metabolism* / Q000648:ultrastructure; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D022142:Secretory Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; D033921:Vesicular Transport Proteins; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D026905:Amino Acid Transport Systems; D002352:Carrier Proteins; C118623:Slc32a1 protein, rat; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; D033921:Vesicular Transport Proteins; D001224:Aspartic Acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D011189:Potassium Chloride; D005998:Glycine