Audesirk G, Strumwasser F
Division of Biology, California Institute of Technology, Pasadena, Calif. 91125.
Proc Natl Acad Sci U S A. 1975 Jun;72(6):2408-12. doi: 10.1073/pnas.72.6.2408.
(1) The neuron R15 in the parietovisceral ganglion of Aplysia has a circadian rhythm of spiking activity when recorded in the isolated ganglion. The rhythm is entrained in vivo by light-dark cycles. (2) The phase of the R15 rhythm is a function not only of the entraining light schedule, but also of the time of dissection. Changes in the dissection time during the light portion of the light-dark cycle yield little change in the subsequent R15 peak time. Dissections during the dark portion produce peak times that vary with dissection time with a slope that is approximately one. (3) The circadian rhythm of R15 can be phase-shifted in vivo by changes in the phase of the entraining light-dark cycle in one to two weeks. R15 neurons of blinded Aplysia, however, show little or no phase shift in this time. (4) It is concluded that the eyes are important as receptors for the photoentrainment of the R15 rhythm in vivo, but that neural connections from the eyes to R15 are not required.
(1) 海兔顶内脏神经节中的R15神经元在分离的神经节中记录时具有放电活动的昼夜节律。该节律在体内受明暗周期的调节。(2) R15节律的相位不仅是调节光照时间表的函数，也是解剖时间的函数。在明暗周期的光照部分改变解剖时间，随后的R15峰值时间变化很小。在黑暗部分进行解剖时，峰值时间随解剖时间而变化，斜率约为1。(3) 通过改变调节明暗周期的相位，R15的昼夜节律在一到两周内可在体内发生相位偏移。然而，失明海兔的R15神经元在此期间几乎没有或没有相位偏移。(4) 得出的结论是，眼睛作为体内R15节律光调节的感受器很重要，但从眼睛到R15的神经连接不是必需的。
