A deep brain photoreceptive molecule in the toad hypothalamus

AbstractWe have isolated a cDNA clone encoding a deep brain photoreceptive molecule from the hypothalamic cDNA library of the toad, Bufo japonicus. The deduced amino acid sequence showed the highest similarity to that of pinopsin (75–76%) among vertebrate retinal opsins, indicating the expression of toad pinopsin in the deep brain. Antibodies raised against the C-terminal tail of toad pinopsin stained cell bodies and the knob-like structures of the cerebrospinal fluid-contacting neurons in the anterior preoptic nucleus. This region is known to play an important role in breeding behavior, suggesting that toad pinopsin acts as a photosensor for the photoperiodic gonadal response

Combined Influences of Gradual Changes in Room Temperature and Light around Dusk and Dawn on Circadian Rhythms of Core Temperature, Urinary 6-Hydroxymelatonin Sulfate and Waking Sensation Just after Rising

The present experiment aimed at knowing how a gradual changes of room temperature (Ta) and light in the evening and early morning could influence circadian rhythms of core temperature (Tcore), skin temperatures, urinary 6-hydroxymelatonin sulfate and waking sensation just after rising in humans. Two kinds of room environment were provided for each participant: 1) Constant room temperature (Ta) of 27 °C over the 24 h and LD-rectangular light change with abrupt decreasing from 3,000 lx to100 lx at 1800,abrupt increasing from 0 lx to 3,000 lx at 0700. 2) Cyclic changes of Ta and with gradual decrease from 3,000 lx to 100 lx onset at 1700 (twilight period about 2 h), with gradual increasing from 0 lx to 3,000 lx onset at 0500 (about 2 h). Main results are summarized as follows: 1) Circadian rhythms of nadir in the core temperature (Tcore) significantly advanced earlier under the influence of gradual changes of Ta and light than no gradual changes of Ta and light. 2) Nocturnal fall of Tcore and morning rise of Tcore were greater and quicker, respectively, under the influence of gradual changes of Ta and light than no gradual changes of Ta and light. 3) Urinary 6-hydroxymelatonin sulfate during nocturnal sleep was significantly greater under the influence of gradual changes of Ta and light. 4) Waking sensation just after rising was significantly better under the influence of gradual changes of Ta and light. We discussed these findings in terms of circadian and thermoregulatory physiology

Reorganization of Corticospinal Projections after Prominent Recovery of Finger Dexterity from Partial Spinal Cord Injury in Macaque Monkeys

We investigated morphologic changes in the corticospinal tract (CST) to understand the mechanism underlying recovery of hand function after lesion of the CST at the C4/C5 border in seven macaque monkeys. All monkeys exhibited prominent recovery of precision grip success ratio within a few months. The trajectories and terminals of CST from the contralesional (n = 4) and ipsilesional (n = 3) hand area of primary motor cortex (M1) were investigated at 5–29 months after the injury using an anterograde neural tracer, biotinylated dextran amine (BDA). Reorganization of the CST was assessed by counting the number of BDA-labeled axons and bouton-like swellings in the gray and white matters. Rostral to the lesion (at C3), the number of axon collaterals of the descending axons from both contralesional and ipsilesional M1 entering the ipsilesional and contralesional gray matter, respectively, were increased. Caudal to the lesion (at C8), axons originating from the contralesional M1, descending in the preserved gray matter around the lesion, and terminating in ipsilesional Laminae VI/VII and IX were observed. In addition, axons and terminals from the ipsilesional M1 increased in the ipsilesional Lamina IX after recrossing the midline, which were not observed in intact monkeys. Conversely, axons originating from the ipsilesional M1 and directed toward the contralesional Lamina VII decreased. These results suggest that multiple reorganizations of the corticospinal projections to spinal segments both rostral and caudal to the lesion originating from bilateral M1 underlie a prominent recovery in long-term after spinal cord injury