Microvesicles isolated from bovine pineal gland specifically accumulate L-glutamate.
Pinealocytes, endocrine cells that synthesize and secrete melatonin, possess a large number of synaptic-like microvesicles (MVs) containing synaptophysin. By monitoring cross-reactivity with anti-synaptophysin antibody, the MVs were highly purified from bovine pineal glands. The purified MVs were morphologically similar to but distinct from neuronal synaptic vesicles by their lack of synapsin I. Immunological study indicated that the MVs contained vacuolar H(+)-ATPase, synaptotagmin and synaptobrevin 2 (VAMP2). The MVs accumulated L-glutamate at the expense of ATP hydrolysis by vacuolar H(+)-ATPase. No uptakes of melatonin, serotonin, noradrenaline, gamma-aminobutyrate or acetylcholine were observed. These results indicated that the MVs are organelles for storage of L-glutamate in pinealocytes and suggested a possibility that pinealocytes transmit glutamate signals by MVs-mediated exocytosis.
Moriyama
Y
Y
Graduate Department of Gene Sciences, Faculty of Sciences, Hiroshima University, Japan.
Yamamoto
A
A
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D027322:Amino Acid Transport System X-AG; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001693:Biological Transport, Active; D002417:Cattle; D005971:Glutamates / Q000378:metabolism*; D007425:Intracellular Membranes / Q000737:chemistry; D018942:Macrolides; D010870:Pineal Gland / Q000378:metabolism*; D051381:Rats; D013572:Synaptic Vesicles / Q000737:chemistry / Q000378:metabolism; D016708:Synaptophysin / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D027322:Amino Acid Transport System X-AG; D000900:Anti-Bacterial Agents; D005971:Glutamates; D018942:Macrolides; D016708:Synaptophysin; C040929:bafilomycin A1; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases