Mutual Effects of Orexin and Bone Morphogenetic Proteins on Gonadotropin Expression by Mouse Gonadotrope Cells.

Orexin plays a key role in the regulation of sleep and wakefulness and in feeding behavior in the central nervous system, but its receptors are expressed in various peripheral tissues including endocrine tissues. In the present study, we elucidated the effects of orexin on pituitary gonadotropin regulation by focusing on the functional involvement of bone morphogenetic proteins (BMPs) and clock genes using mouse gonadotrope LßT2 cells that express orexin type 1 (OX1R) and type 2 (OX2R) receptors. Treatments with orexin A enhanced LHß and FSHß mRNA expression in a dose-dependent manner in the absence of GnRH, whereas orexin A in turn suppressed GnRH-induced gonadotropin expression in LßT2 cells. Orexin A downregulated GnRH receptor expression, while GnRH enhanced OX1R and OX2R mRNA expression. Treatments with orexin A as well as GnRH increased the mRNA levels of Bmal1 and Clock, which are oscillational regulators for gonadotropin expression. Of note, treatments with BMP-6 and -15 enhanced OX1R and OX2R mRNA expression with upregulation of clock gene expression. On the other hand, orexin A enhanced BMP receptor signaling of Smad1/5/9 phosphorylation through upregulation of ALK-2/BMPRII among the BMP receptors expressed in LßT2 cells. Collectively, the results indicate that orexin regulates gonadotropin expression via clock gene expression by mutually interacting with GnRH action and the pituitary BMP system in gonadotrope cells.

[Myoclonus following spinal and epidural anesthesia--a case report].

We report a case of spinal myoclonus following cesarean section. The patient was a 34-year-old woman without history of neurologic disorders. In the operating room, after placement of an epidural catheter at T12-L1, bupivacaine 2.4 ml was administered intrathecally via a 25 G needle at L2-3. Epidural administration of ropivacaine (0.13%, 4 ml x hr(-1)) was started 72 min after spinal anesthesia. The intra- and postoperative courses were otherwise uneventful. The patient complained of involuntary jerky movements of her lower legs 195 min after the start of the spinal anesthesia. The sensory level was T12 and she could move her legs on command but could not stop her involuntary movements. The myoclonic movements ceased 150 min later without medication and did not reappear, despite restarting the epidural anesthesia with ropivacaine.

[The use of "laryngospasm notch" in two patients whose oxygen saturations dropped after tracheal extubation].

In 1998, Dr. Larson described the technique of applying pressure to the "laryngospasm notch" as the best treatment for laryngospasm. Yet, there are no case reports of using this technique in the literature. We report 2 cases of using this technique in patients whose oxygen saturation levels dropped after tracheal extubation. The first patient was a 48-year-old man who underwent laparoscopic cholecystectomy and the second patient was a 67-year-old man who underwent lumbar laminectomy. In both cases, induction of general anesthesia and surgery were uneventful. After surgery, we confirmed spontaneous respiration and the patients were able to respond and shake hands. However, immediately after extubation, the patients could not breathe and their oxygen saturation levels decreased to 76% and 84%, respectively. In the first patient, mask ventilation was easy and we used the "laryngospasm notch" technique during ventilation. However, in the second patient, mask ventilation was difficult and we used this technique prepared for re-intubation. In both cases, the patients began to breathe spontaneously shortly after using this technique and oxygen saturation increased to 100%. The incidence of laryngospasm is higher after tracheal extubation. The "laryngospasm notch" method is a good technique to treat this condition.

[Taste loss following the use of the laryngeal mask airway].

The laryngeal mask airway can be used safely to manage the airway. However, it is associated with a few complications. We report a case of taste loss following the use of the laryngeal mask airway in a 20-year-old man. He was scheduled for open reduction and internal fixation of fractured bones. Anesthesia was induced with propofol and maintained with nitrous oxide, oxygen and sevoflurane. The patient complained of loss of taste on the first postoperative day. Taste loss lasted for six months. We conclude that loss of taste was caused by lingual nerve injury associated with malposition of the laryngeal mask airway.

Gustatory coding in the precentral extension of area 3 in Japanese macaque monkeys; comparison with area G.

The precentral extension of area 3 as well as the transition between the frontal operculum and insula (area G) comprises the primary gustatory cortex in the subhuman primate, receiving projections from the thalamic taste relay. However, in contrast to the extensive studies that have been carried out on the latter area, only a few taste units in the former area have been recorded. To clarify gustatory coding in area 3, we investigated the taste response properties of neurons in area 3 compared with those in area G in alert monkeys by infiltrating into their mouths seven taste stimuli [0.3 M sucrose (S), 0.1 M NaCl (N), 0.01 N HCl (H), 0.003 M quinine-HCl (Q), 0.1 M monosodium glutamate (MSG), distilled water (W), and orange juice (OR)] and artificial saliva (SA). A larger number of HCl-best units and a smaller number of quinine-best units were found in area 3 than in area G. The onset latency and response duration were significantly shorter in area 3 than in area G. Weighted multi-dimensional scaling showed that area G divided eight stimulants into four classes, i.e. two groups (H-Q-W and S-MSG-OR), N and SA, whereas area 3 divided them into three classes (N-MSG-W-OR, S-Q, and H-SA). This suggested that tastants not separated in area G were separated in area 3, and vice versa. This indicates that both areas complement each other in the representation of taste stimuli, each contributing to taste information processing in a different manner.

Neuronal activities in the monkey primary and higher-order gustatory cortices during a taste discrimination delayed GO/NOGO task and after reversal.

The correlation between different gustatory areas in the frontal operculum, orbitofrontal area, and insula and the representation of different aspects of cues during a salt-water discrimination delayed GO/NOGO task was studied in a Japanese monkey. Four groups were identified among 169 neurons responding to cues before/after task reversal. Group I (n=78) responded to the physicochemical nature of the cue, Group II (n=8) responded to both the physicochemical nature of the cue and the subsequent behavior, Group III (n=51) (three subgroups) produced discharges related to the subsequent behavior, and Group IV (n=32) produced non-differential responses probably related to attention. The primary gustatory areas (area G and the oral part of area 3) almost exclusively contained Group I neurons, whereas the so-called secondary gustatory areas (the PrCO and area 12) contained most of the Group III neurons. Group IIIc showed discharges accelerating to the LED onset, probably representing preparation for subsequent behavior, and the response differed between the PrCO and area 12. The PrCO also contained Group IV neurons. The primary gustatory areas process pure gustatory signals, whereas the PrCO and area 12 may be involved in gustatory perception, attention, or behavior.