Co. Okere et al., FAILURE OF INTRABULBAR AND PERIPHERAL ADMINISTRATION OF N-OMEGA-NITRO-L-ARGININE TO PREVENT THE FORMATION OF AN OLFACTORY MEMORY IN MICE, Physiology & behavior, 58(2), 1995, pp. 387-391
The gaseous neurotransmitter molecule nitric oxide (NO) has recently g
enerated a lot of interest on account of its possible physiological ro
le in several models of learning and memory, both in vitro and in vivo
. The presence of its synthesizing enzyme has been reported in the gra
nule cell and external plexiform layers of the accessory olfactory bul
b (AOB) in mice and rats. We have tested the effect of different doses
of the nitric oxide synthase inhibitor, N-w-nitro-L-arginine applied
locally and peripherally, on the formation of olfactory recognition me
mory in the context of pregnancy block in mice. Local infusions of 5,
10, and 40 nmol of the NOS inhibitor into the AOB Failed to prevent me
mory formation of the stud male without affecting the effectiveness of
the strange male to induce pregnancy block. Peripheral administration
of the NOS inhibitor produced a pregnancy block rate that was linearl
y related to the dose regardless of whether or not exposure to the fam
iliar or no male subsequently followed. This suggests that the effect
of peripheral administration of the NOS inhibitor on memory formation
could not be assessed using this experimental paradigm. The observatio
ns made in this study do not enable us to envisage any critical or pri
mary physiological role for NO in this memory model. Its role, at best
, may be modulatory and not obligatory.