Avtor/Urednik     Osredkar, D; Burnik-Papler, T; Pečavar, B; Kralj-Iglič, V; Kržan, M
Naslov     Kinetic and pharmacological properties of [(3)H]-histamine transport into cultured type 1 astrocytes from neonatal rats
Tip     članek
Vir     Inflamm Res
Vol. in št.     Letnik 58, št. 2
Leto izdaje     2009
Obseg     str. 94-102
ISSN     1023-3830
Jezik     eng
Abstrakt     Objective and design: Astrocytes actively participate in the inactivation of neurotransmitters. In this work we elucidated the contribution of astrocytes in clearance of histamine, a process which has not yet been fully clarified.Methods: The characteristics of [(3)H]-histamine uptake were determined in cultured neonatal rat type 1 astrocytes and histamine-N-methyl-transferase expression was determined using RT-PCR.Results: These cells transport [(3)H]-histamine in a time- and concentration-dependent manner. The histamine clearance by astrocytes was described by a mathematical model including two processes: electrodiffusion and active transport. A further analysis of kinetic parameters of a carrier-operated transport revealed a single transport system with Michaelis constant (K(m)) of 3.5 +/- 0.8 muM and a maximal uptake rate (V(max)) of 7.9 +/- 0.3 pmol/mg protein/min. From drugs tested amitriptyline, desipramine, mepyramine and cimetidine significantly decreased [(3)H]-histamine uptake. Taken-up histamine could be metabolically degraded in cultured astrocytes, since they express mRNA for enzyme histamine-N-methyltransferase.Conclusion: Astrocytes participate in the clearance of extracellular histamine by electrodiffusion and active transport by a yet not identified carrier. Taken up histamine can be converted to tele-methylhistamine within astrocytes thus indicating the involvement of astrocytes not only in clearance but also in the inactivation of histamine.
Deskriptorji     ASTROCYTES
HISTAMINE
HISTAMINE METHYLTRANSFERASE
BIOLOGICAL TRANSPORT, ACTIVE
POLYMERASE CHAIN REACTION
KINETICS
CELLS, CULTURED
ANIMALS, NEWBORN
RATS, WISTAR