A. Jachimowicz et al., THE PARTICIPATION OF NITRIC-OXIDE IN THE FACILITATOR EFFECT OF ARGININE-VASOPRESSIN ON MEMORY, Acta Neurobiologiae Experimentalis, 58(1), 1998, pp. 37-45
In this study we tested the hypothesis that nitric oxide (NO), which f
unction as a novel type of inter-cellular messenger in the central ner
vous system (CNS) participated in the facilitator effect of arginine v
asopressin (AVP) on learning and memory. Recent investigations have pr
ovided evidences that inhibition of NO synthesis attenuated the vasodi
latation caused by AVP, and inhibited the improvement of learning and
memory evoked by angiotensin II, AVP as well as pharmacologically prod
uced increase in endogenous NO facilitates the consolidation of shock
avoidance learning. We evaluated the behavioural effects of AVP at dos
e 1 mu g after the inhibition of NOS by N-G-nitro-L-arginine methyl es
ter (L-NAME) at dose 10 mu g, and after the injection of endogenous do
nor of NO-L-argnine-10 mu g in the retrieval of passive avoidance situ
ation, and in consolidation of active avoidance responses. The locomot
or activity of all investigated drugs was tested in the open field tes
t. AVP facilitated the recall of passive avoidance responses and conso
lidation of active avoidance responses. Neither the increase of NO con
centration after the injection of L-arginine nor the decrease of NO af
ter the inhibition of NOS by L-NAME changed the behavioural effects of
AVP. L-arginine increased the psychomotor behaviour and L-NAME decrea
sed the activity of animals in the ''open field'' test. L-arginine its
elf improved the consolidation of active avoidance responses. Our resu
lts indicate that central action of AVP is probably independent of NO
concentration in the brain.