Reiko Saito

Possible Involvement of the Rat Hypothalamo-Neurohypophysial/-Spinal Oxytocinergic Pathways in Acute Nociceptive Responses.

Oxytocin (OXT)‐containing neurosecretory cells in the parvocellular divisions of the paraventricular nucleus (PVN), which project to the medulla and spinal cord, are involved in various physiological functions, such as sensory modulation and autonomic processes. In the present study, we examined OXT expression in the hypothalamo‐spinal pathway, as well as the hypothalamo‐neurohypophysial system, which includes the magnocellular neurosecretory cells in the PVN and the supraoptic nucleus (SON), after s.c. injection of saline or formalin into the hindpaws of transgenic rats that express the OXT and monomeric red fluorescent protein 1 (mRFP1) fusion gene. (i) The numbers of OXT‐mRFP1 neurones that expressed Fos‐like immunoreactivity (‐IR) and OXT‐mRFP1 intensity were increased significantly in the magnocellular/parvocellular PVN and SON after s.c. injection of formalin. (ii) OXT‐mRFP1 neurones in the anterior parvocellular PVN, which may project to the dorsal horn of the spinal cord, were activated by s.c. injection of formalin, as indicated by a significant increases of Fos‐IR and mRFP1 intensity intensity. (iii) Formalin injection caused a significant transient increase in plasma OXT. (iv) OXT, mRFP1 and corticotrophin‐releasing hormone mRNAs in the PVN were significantly increased after s.c. injection of formalin. (v) An intrathecal injection of OXT‐saporin induced hypersensitivity in conscious rats. Taken together, these results suggest that the hypothalamo‐neurohypophysial/‐spinal OXTergic pathways may be involved in acute nociceptive responses in rats.

Mutation spectrum and phenotypic variation in nine patients with SOX2 abnormalities

Multiple mutations in SOX2 have been identified in patients with ocular anomalies and/or pituitary dysfunction. Here, we identified SOX2 abnormalities in nine patients. The molecular defects included one missense, one nonsense and four frameshift mutations, and three submicroscopic deletions involving SOX2. Three of the six mutations and all deletions were hitherto unreported. The breakpoints determined in one deletion were located within Alu repeats and accompanied by an overlap of 11 bp. Three of the six mutations encoded SOX2 proteins that lacked in vitro transactivation activity for the HESX1 promoter, whereas the remaining three generated proteins with ∼15–∼20% of transactivation activity. All cases manifested ocular anomalies of various severities, together with several complications including arachnoid cyst and hamartoma. There was no apparent correlation between the residual activity and clinical severity. The results indicate that molecular defects in SOX2 are highly variable and include Alu repeat-mediated genomic rearrangements. Our data provide further evidence for wide phenotypic variation of SOX2 abnormalities and the lack of genotype–phenotype correlation in patients carrying SOX2 lesions.

Involvement of central nesfatin-1 neurons on oxytocin-induced feeding suppression in rats

Peripheral anorectic hormones, such as peptide YY (PYY) and oxytocin (OXT), suppress food intake. A newly identified anorectic neuropeptide, nesfatin-1, is synthesized in both peripheral tissue and the central nervous system, particularly by various nuclei in the hypothalamus and brainstem. Here, we examined the effects of intraperitoneal (ip) administration of PYY3-36, OXT, and OXT analog, on nesfatin-1-immunoreactive (ir) neurons in the rat hypothalamus and brainstem, using Fos double fluorescence-immunohistochemistry. The ip administration of OXT and OXT analog significantly increased the number of nesfatin-1-ir neurons expressing Fos-ir in the paraventricular nucleus, the arcuate nucleus, and the nucleus tractus solitarius, but not in the supraoptic nucleus, the lateral hypothalamic area, and the area postrema. No differences in the percentage of nesfatin-1-ir neurons expressing Fos in the nuclei of the hypothalamus and brainstem were observed, between rats treated with vehicle or those treated with PYY3-36. The decreased food intake, induced by OXT and OXT analog, was attenuated significantly by pretreatment with intracerebroventricular administration of antisense nesfatin-1. These results suggested that nesfatin-1-expressing neurons in the hypothalamus and brainstem may play a role in sensing the peripheral level of OXT and its suppression of feeding in rats.

Comparison of the induction of c-fos-eGFP and Fos protein in the rat spinal cord and hypothalamus resulting from subcutaneous capsaicin or formalin injection

We evaluated whether a c-fos-enhanced green fluorescent protein (eGFP) transgenic rat line, which expresses the c-fos and eGFP fusion gene, can be useful for the study of nociceptive pathways and processing. Capsaicin solution (15%) or formalin (5%) was subcutaneously injected bilaterally into the hind paws (100μL per each paw) of adult male c-fos-eGFP transgenic or wild-type rats. Control rats were injected with ethanol or physiological saline respectively. Transgenic and wild-type rats were perfused at 1.5, 3 and 6h post injection, with some transgenic rats being perfused 24h post injection. A comparison of eGFP in transgenic rats and Fos-like immunoreactivity (LI) in wild-type rats was made in the dorsal spinal cord, paraventricular nucleus (PVN) and supraoptic nucleus (SON). Oxytocin-LI (OXT-LI) was carried out to examine the activation of OXT neurons in the PVN and SON. Following capsaicin or formalin treatment, eGFP was maximally expressed at 6h in the spinal cord and 3h in the PVN and SON, whereas, Fos-LI was maximally expressed at 1.5h in all the regions we analyzed. Induction of eGFP in the OXT neurons was observed after capsaicin or formalin treatment, while Fos-LI in the OXT neurons was observed only after formalin treatment. These results demonstrate that the peak induction of c-fos-eGFP following exposure to acute nociceptive stimuli was delayed by around 1.5-4.5h, but more sensitive than endogenous Fos, suggesting that the c-fos-eGFP rat line can be useful for the study of nociceptive pathways and processing.

Effects of central administration of oxytocin-saporin cytotoxin on chronic inflammation and feeding/drinking behaviors in adjuvant arthritic rats

An increase in the arthritis index as a marker of chronic inflammation and suppression of food intake are observed in adjuvant arthritic (AA) rats. Our previous study demonstrated that central oxytocin (OXT)-ergic pathways were activated potently in AA rats. In the present study, OXT-saporin (SAP) cytotoxin, which chemically disrupts OXT signaling was administered centrally to determine whether central OXT may be involved in the developments of chronic inflammation and alteration of feeding/drinking behavior in AA rats. The arthritis index was significantly enhanced in AA rats pretreated with OXT-SAP administered intrathecally (i.t.) but not intracerebroventricularly (i.c.v.). Suppression of food intake was significantly attenuated transiently in AA rats pretreated with OXT-SAP administered i.c.v. but not i.t. Suppression of drinking behavior was not affected by i.t. or i.c.v. administration of OXT-SAP in AA rats. In addition, intraperitoneal administration of an OXT receptor antagonist did not change the arthritis index or feeding/drinking behavior in AA rats. These results suggest that central OXT-ergic pathways may be involved in anti-inflammation at the spinal level and suppression of feeding behavior at the forebrain-brainstem level in AA rats.

Sporadic pseudohypoparathyroidism type-1b with asymptomatic hypocalcemia

Pseudohypoparathyroidism type 1b (PHP‐1b) is usually diagnosed on various symptoms of hypocalcemia. Previous studies reported a few cases of autosomal dominant pattern PHP‐1b identified on familial analysis with asymptomatic hypocalcemia. Herein we report the case of a 6‐year‐old male patient with sporadic PHP‐1b incidentally detected on preoperative examination. He had neither characteristic findings of Albright hereditary osteodystrophy nor evidence of tetany. Sporadic PHP‐1b was diagnosed on the basis of clinical observation and laboratory examination. In addition, genetic testing using methylation‐specific multiplex ligation‐dependent probe amplification indicated broad methylation abnormalities and confirmed the sporadic form of PHP‐1b. Sporadic PHP‐1b might often be overlooked when diagnosis is done simply on definitive clinical features. To avoid this, DNA sequencing and methylation analysis should be performed even in the absence of definitive clinical features.

Tamoxifen Treatment for Pubertal Gynecomastia in Two Siblings with Partial Androgen Insensitivity Syndrome

Background: Although tamoxifen has been shown to be fairly safe and effective for idiopathic pubertal gynecomastia, it remains unknown whether it is also beneficial for gynecomastia associated with endocrine disorders. Here, we report the effect of tamoxifen on pubertal gynecomastia in 2 siblings with partial androgen insensitivity syndrome (PAIS). Case Reports: Cases 1 and 2 presented with persistent pubertal gynecomastia at 13 and 16 years of age, respectively. Physical examinations revealed breast of Tanner stage 3 and normal male-type external genitalia in both cases. Clinical features such as female-type pubic hair and borderline small testis indicated mildly impaired masculinization. Results: Molecular analysis identified a previously reported p.Arg789Ser mutation in the androgen receptor gene (AR) in the 2 cases. Two months of oral administration of tamoxifen ameliorated gynecomastia to Tanner stage 2 with no adverse events. Additional treatment with testosterone enanthate showed negligible effects on body hair and penile length. Hormone values of the 2 cases during tamoxifen treatment remained similar to those in previously reported untreated patients with PAIS. Conclusion: The results indicate that tamoxifen was effective in treating pubertal gynecomastia in these 2 patients with PAIS and may be considered as a therapeutic option in this situation pending further studies.

Possible involvement of central oxytocin in cisplatin-induced anorexia in rats

During cancer chemotherapy, drugs such as 5-HT3 receptor antagonists have typically been used to control vomiting and anorexia. We examined the effects of oxytocin (OXT), which has been linked to appetite, on cisplatin-induced anorexia in rats. Fos-like immunoreactivity (Fos-LI) expressed in the supraoptic nucleus (SON), the paraventricular nucleus (PVN), the area postrema and the nucleus of the solitary tract (NTS) after intraperitoneal (ip) administration of cisplatin. We also examined the fluorescence intensity of OXT-mRFP1 after ip administration of cisplatin in OXT-mRFP1 transgenic rats. The mRFP1 fluorescence intensity was significantly increased in the SON, the PVN, and the NTS after administration of cisplatin. The cisplatin-induced anorexia was abolished by OXT receptor antagonist (OXTR-A) pretreatment. In the OXT-LI cells, cisplatin-induced Fos expression in the SON and the PVN was also suppressed by OXTR-A pretreatment. These results suggested that central OXT may be involved in cisplatin-induced anorexia in rats.

Increased oxytocin-monomeric red fluorescent protein 1 fluorescent intensity with urocortin-like immunoreactivity in the hypothalamo-neurohypophysial system of aged transgenic rats

To visualize oxytocin in the hypothalamo-neurohypophysial system, we generated a transgenic rat that expresses the oxytocin-monomeric red fluorescent protein 1 (mRFP1) fusion gene. In the present study, we examined the age-related changes of oxytocin-mRFP1 fluorescent intensity in the posterior pituitary (PP), the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) of transgenic rats. The mRFP1 fluorescent intensities were significantly increased in the PP, the SON and the PVN of 12-, 18- and 24-month-old transgenic rats in comparison with 3-month-old transgenic rats. Immunohistochemical staining for urocortin, which belongs to the family of corticotropin-releasing factor family, revealed that the numbers of urocortin-like immunoreactive (LI) cells in the SON and the PVN were significantly increased in 12-, 18- and 24-month-old transgenic rats in comparison with 3-month-old transgenic rats. Almost all of urocortin-LI cells co-exist mRFP1-expressing cells in the SON and the PVN of aged transgenic rats. These results suggest that oxytocin content of the hypothalamo-neurohypophysial system may be modulated by age-related regulation. The physiological role of the co-existence of oxytocin and urocortin in the SON and PVN of aged rats remains unclear.

Elevated endogenous secretory receptor for advanced glycation end products (esRAGE) levels are associated with circulating soluble RAGE levels in diabetic children.

Abstract Background: Advanced glycation end products (AGEs) and the receptor for AGE (RAGE) play an important role in the development of diabetic vascular complications. This study aimed at investigating the relationship between the soluble form of RAGE (sRAGE), endogenous secretory RAGE (esRAGE), and pentosidine in childhood diabetes. Methods: The study included 18 children with type 1 diabetes mellitus (T1DM), 10 with type 2 DM (T2DM), and 22 age-matched, non-diabetic children (control). Results: Serum sRAGE levels in the T1DM (2557.7 pg/mL) were significantly higher than both T2DM (1956.4 pg/mL) and control (1658.5 pg/mL). The circulating levels of esRAGE in T1DM and T2DM children were similar, but significantly higher than those of control. Serum pentosidine levels in the T1DM group were positively correlated with serum sRAGE and esRAGE levels, but not with anthropometric or biochemical measurements. The duration of diabetes and esRAGE levels were independent predictors of the circulating sRAGE levels. Conclusions: Unlike adults, children with diabetes exhibit high circulating esRAGE levels, and both sRAGE and esRAGE levels are correlated with pentosidine levels. These results suggest that circulating sRAGE and esRAGE in children may be surrogate markers for progressive glucose toxicity in pediatric patients with childhood-onset diabetes.