TY - JOUR
T1 - Avian melatonin synthesis
T2 - Photic and circadian regulation of serotonin N-acetyltransferase mRNA in the chicken pineal gland and retina
AU - Bernard, Marianne
AU - Iuvone, P. Michael
AU - Cassone, Vincent M.
AU - Roseboom, Patrick H.
AU - Coon, Steven L.
AU - Klein, David C.
PY - 1997/1
Y1 - 1997/1
N2 - The circadian rhythms in melatonin production in the chicken pineal gland and retina reflect changes in the activity of serotonin N- acetyltransferase (arylalkyl-amine N-acetyltransferase; AA-NAT; EC 2.3.1.87). Here we determined that the chicken AA-NAT mRNA is detectable in follicular pineal cells and retinal photoreceptors and that it exhibits a circadian rhythm, with peak levels at night. AA-NAT mRNA was not detected in other tissues. The AA-NAT mRNA rhythm in the pineal gland and retina persists in constant darkness (DD) and constant lighting (LL). The amplitude of the pineal mRNA rhythm is not decreased in LL. Light appears to influence the phase of the clock driving the rhythm in pineal AA-NAT mRNA in two ways: The peak is delayed by ~6 h in LL, and it is advanced by >4 h by a 6-h light pulse late in subjective night in DD. Nocturnal AA-NAT mRNA levels do not change during a 20-min exposure to light, whereas this treatment dramatically decreases AA-NAT activity. These observations suggest that the rhythmic changes in chicken pineal AA-NAT activity reflect, at least in part, clock- generated changes in mRNA levels. In contrast, changes in mRNA content are not involved in the rapid light-induced decrease in AA-NAT activity.
AB - The circadian rhythms in melatonin production in the chicken pineal gland and retina reflect changes in the activity of serotonin N- acetyltransferase (arylalkyl-amine N-acetyltransferase; AA-NAT; EC 2.3.1.87). Here we determined that the chicken AA-NAT mRNA is detectable in follicular pineal cells and retinal photoreceptors and that it exhibits a circadian rhythm, with peak levels at night. AA-NAT mRNA was not detected in other tissues. The AA-NAT mRNA rhythm in the pineal gland and retina persists in constant darkness (DD) and constant lighting (LL). The amplitude of the pineal mRNA rhythm is not decreased in LL. Light appears to influence the phase of the clock driving the rhythm in pineal AA-NAT mRNA in two ways: The peak is delayed by ~6 h in LL, and it is advanced by >4 h by a 6-h light pulse late in subjective night in DD. Nocturnal AA-NAT mRNA levels do not change during a 20-min exposure to light, whereas this treatment dramatically decreases AA-NAT activity. These observations suggest that the rhythmic changes in chicken pineal AA-NAT activity reflect, at least in part, clock- generated changes in mRNA levels. In contrast, changes in mRNA content are not involved in the rapid light-induced decrease in AA-NAT activity.
KW - Circadian rhythm
KW - Light
KW - Melatonin
KW - Molecular cloning
KW - Pineal gland
KW - Retina
KW - Serotonin N-acetyltransferase
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U2 - 10.1046/j.1471-4159.1997.68010213.x
DO - 10.1046/j.1471-4159.1997.68010213.x
M3 - Article
C2 - 8978728
AN - SCOPUS:0031020569
SN - 0022-3042
VL - 68
SP - 213
EP - 224
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
IS - 1
ER -