Keratinocytes: a source of the transmitter L-glutamate in the epidermis.
Various glutamate receptors have been described in both keratinocytes and melanocytes. L-Glutamate is the physiological agonist of the glutamate receptor family. The source of this transmitter had not yet been identified. In normal human epidermal keratinocytes (NHEK) and HaCaT-keratinocytes, cell supernatants were sampled in various stages of cell density and the l-glutamate content photometrically determined. The following examination time-points were defined: non-confluent (ca. 33%), subconfluent (ca. 70%) and confluent (90-100%). The L-glutamate concentration originally in the culture medium was 14.7 mg/l (0.1 mm/l). The L-glutamate concentration in the cell supernatant increased in NHEK with increasing cell density: non-confluent 39.9 + or - 4 mg/l, subconfluent 60.6 + or - 15.8 mg/l, confluent 100.7 + or - 33.2 mg/l. A linear increase of L-glutamate concentration was also found for HaCaT cells. The investigations show that keratinocytes are capable of producing and releasing L-glutamate. Thus they are a source of L-glutamate which acts as a transmitter on epidermal glutamate receptors.
Fischer
Matthias
M
Department of Dermatology and Venerology, HELIOS-Klinikum Aue, Gartenstrasse 6, D-08280 Aue, Germany. matthias.fischer@helios-kliniken.de
Glanz
Dagobert
D
Urbatzka
Maximilian
M
Brzoska
Thomas
T
Abels
Christoph
C
D002452:Cell Count; D002460:Cell Line; D017077:Culture Media, Conditioned / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D017470:Receptors, Glutamate / Q000378:metabolism
D017077:Culture Media, Conditioned; D018377:Neurotransmitter Agents; D017470:Receptors, Glutamate; D018698:Glutamic Acid