INTRAVITREAL APPLICATION OF MEMBRANE-PERMEABLE ANALOGS OF CYCLIC-GMP INCREASES SEROTONIN N-ACETYLTRANSFERASE (NAT) ACTIVITY IN RETINAS OF LIGHT-EXPOSED CHICKS - COMPARISON WITH THE EFFECT OF CYCLIC-AMP ANALOGSAND DARKNESS
Jz. Nowak et M. Wawrocka, INTRAVITREAL APPLICATION OF MEMBRANE-PERMEABLE ANALOGS OF CYCLIC-GMP INCREASES SEROTONIN N-ACETYLTRANSFERASE (NAT) ACTIVITY IN RETINAS OF LIGHT-EXPOSED CHICKS - COMPARISON WITH THE EFFECT OF CYCLIC-AMP ANALOGSAND DARKNESS, Neuroscience letters, 162(1-2), 1993, pp. 21-24
Intravitreal administration of membrane-permeable analogs of cGMP and
cAMP markedly enhanced serotonin N-acetyltransferase (NAT) activity in
retinas of light-exposed chicks. The effects of cGMP analogs were usu
ally weaker than the actions of cAMP analogs, however, they were more
pronounced than the effects of non-cyclic derivative of GMP (i.e., 8-b
romo-GMP). Combined treatment with dibutyryl-derivatives of cGMP and c
AMP yielded NAT values that were similar to the values produced by the
compounds administered separately, whereas NAT activity in chicks rec
eiving a combination of db-cGMP and aminophylline was higher than the
enzyme activity produced by the drugs individually. Neither db-cGMP no
r aminophylline affected hydroxyindole-O-methyltransferase (HIOMT) act
ivity in retinas of light-exposed chicks. It is hypothesized that cGMP
analogs enhance the retinal NAT activity indirectly, via cAMP.