Nürnberger F, Joshi B N, Heinzeller T, Milin J, Reiter R J
J Pineal Res. 1985;2(4):375-86. doi: 10.1111/j.1600-079x.1985.tb00717.x.
In three separate experiments, the effect of acute exposure to either artificial or natural light during darkness of pineal N-acetyltransferase (NAT) activity and melatonin content was studied in the cotton rat (Sigmodon hispidus). The exposure of animals to an artificial-light irradiance of 160,000 microW/cm2 during darkness for either 1 s, 5 s, or 30 min was followed by a precipitous decline in pineal NAT activity and melatonin content when measured at either 15 or 30 min after light onset. When cotton rats were acutely exposed to light at night for 5 s, irradiances of either 3.2, 32, 320, and 3,200 did not suppress either pineal NAT or melatonin 30 min later; however, if the 5-s exposure had an irradiance of either 32,000 or 160,000 microW/cm2, the pineal enzyme activity and indole content were depressed. Moonlight, which had a maximal irradiance of 0.32 microW/cm2, was unable to suppress pineal NAT activity and melatonin content even when the animals were exposed to the moonlight for 30 min. The treatment of cotton rats with either norepinephrine or its agonist, isoproterenol, before their exposure to light at night retarded slightly the suppressive effect of light on the pineal constituents measured. Also, these drug treatments suppressed the pre-exposure levels of both NAT activity and melatonin content in the cotton rat pineal gland.
在三项独立实验中，研究了棉鼠（棉鼠属棉鼠）在黑暗中急性暴露于人造光或自然光对松果体N - 乙酰转移酶（NAT）活性和褪黑素含量的影响。在黑暗中，将动物暴露于160,000微瓦/平方厘米的人造光辐照下1秒、5秒或30分钟，在光照开始后15分钟或30分钟测量时，松果体NAT活性和褪黑素含量会急剧下降。当棉鼠在夜间急性暴露于光照5秒时，3.2、32、320和3200的辐照度在30分钟后均未抑制松果体NAT或褪黑素；然而，如果5秒暴露的辐照度为32,000或160,000微瓦/平方厘米，则松果体酶活性和吲哚含量会降低。最大辐照度为0.32微瓦/平方厘米的月光，即使动物暴露于月光下30分钟，也无法抑制松果体NAT活性和褪黑素含量。在棉鼠夜间暴露于光照之前，用去甲肾上腺素或其激动剂异丙肾上腺素进行处理，会略微延缓光照对所测松果体成分的抑制作用。此外，这些药物处理还抑制了棉鼠松果体中NAT活性和褪黑素含量的暴露前水平。
