Hippocampal Vasopressin Release Evoked by N-Methyl D-Aspartate
(NMDA) Microdialysis
M. ORŁOWSKA-MAJDAK, W. Z.
TRACZYK, D. SZYMAŃSKI
Department of Experimental and Clinical Physiology,
Institute of Physiology and Biochemistry, Medical
University of Łódź, Poland
Received February 13, 2002
Accepted July 30, 2002
Summary
Hippocampus is a brain structure containing vasopressin (AVP)
fibers and specific binding sites for this peptide. There is
growing evidence that AVP and its metabolites participate in
glutamate-mediated plasticity of the hippocampus. The aim of the
present study was to evaluate the influence of NMDA on AVP
release in the rabbit hippocampus. Caudate nucleus was chosen as
the reference structure. The mentioned brain structures were
simultaneously microdialyzed with 0.9 % NaCl solution. AVP was
determined in the outflowing fluid by radioimmunoassay. The mean
basal AVP content in the fluid outflowing from the hippocampus
was significantly greater than that from the caudate nucleus.
The addition of K+ into the fluid perfusing the
probes implanted into the hippocampus and caudate nucleus
significantly increased AVP release into the extracellular fluid
of both brain structures. NMDA applied into the mentioned brain
structures increased AVP release only from the hippocampus but
not from the caudate nucleus. Our findings indicate a role which
NMDA receptors play in AVP release into the extracellular fluid
of the hippocampus.
Key
words
FHippocampus • Caudate nucleus • Microdialysis • NMDA • K+
• Vasopressin • Rabbit
Reprint
requests
Monika Orłowska-Majdak, Department of Experimental and Clinical
Physiology, Institute of Physiology and Biochemistry, Medical
University of Łódź, Mazowiecka 6/8, 92-215 Łódź, Poland, e-mail:
morlowska@zdn.am.lodz.pl
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