GLUTAMATERGIC MODULATION OF HYPOTHALAMIC RSPONDIN3 NEURONS UNDER PHYSIOLOGICAL CONDITIONS


Gök Yurtseven D., Topal G., Hasanoğlu Akbulut N., Udum D., Yalçın M., Eyigör Ö.

17 International Congress of Histochemistry and Cytochemistry, Rimini, İtalya, 27 - 30 Ağustos 2025, cilt.69, sa.29, ss.33, (Özet Bildiri)

  • Yayın Türü: Bildiri / Özet Bildiri
  • Cilt numarası: 69
  • Doi Numarası: 10.4081/ejh.2025.4349
  • Basıldığı Şehir: Rimini
  • Basıldığı Ülke: İtalya
  • Sayfa Sayıları: ss.33
  • Bursa Uludağ Üniversitesi Adresli: Evet

Özet

Food intake is a complex behavior regulated by neuropeptides released from the central nervous system. R-spondin (Rspo) pep-tides are expressed at the mRNA level in hypothalamic regions involved in feeding behavior and play a role in appetite regula-tion1. The glutamatergic system, as a major excitatory neurotrans-mitter in the hypothalamus, regulates many endocrine and pep-tidergic systems2. However, there is limited information about neurotransmitter control of R-spondin neurons, and no data exist regarding glutamatergic modulation.This study investigated whether Rspo3-expressing hypothalamic neurons are activated after refeeding or glucose administration following 48 h of fasting, and whether this activation can be suppressed by glutamatergic antagonists. c-Fos was used as a neuronal activation marker. Sprague Dawley rats (5 males and 5 females per group) were divided into seven groups receiving combinations of fasting, refeeding, glucose, CNQX (2 mg/kg), or MK-801 (0.05 or 1 mg/kg). Coronal brain sections (40 μm) were processed for Rspo3/c-Fos immunoperoxidase labeling. Double-labeled neurons were quantified in SON, PVN, and ARC. Plasma Rspo3 levels were measured by ELISA. The percentage of activated Rspo3 neu-rons in SON, PVN, and ARC was respectively: fasting (1.53%, 6.54%, 7.95; 6.90%, 13.01%, 27.26), refeeding (93.67%, 75.72%, 1.11; 82.15%, 45.84%, 19.76), and CNQX+refeeding (9.24%, 9.34%, 2.74; 17.02%, 5.69%, 11.31). Glucose injec-tion increased Rspo3 activation, which was suppressed by antago-nist pretreatment (p<0.001). ELISA confirmed that refeeding ele-vated Rspo3 levels, which were reduced by CNQX to control-like values (p<0.05). Glucose protocols revealed significant group dif-ferences in both sexes (p<0.05). These findings show that refeed-ing or glucose activates Rspo3 neurons through glutamatergic mechanisms involving c-Fos, supported by peripheral ELISA data.