Various studies contributed to discover novel mechanisms of central arginine vasopressin (AVP) system responsible for the behaviour albeit endogenous vasopressin activation. We established a novel transgenic rat line which expresses both human muscarinic acetylcholine receptors (hM3Dq), of which ligand is clozapine-N-oxide (CNO), and mCherry fluorescence specifically in AVP neurons. The mCherry neurons that indicate the expression of the hM3Dq gene were observed in the suprachiasmatic (SCN), supraoptic (SON), and paraventricular nuclei (PVN). hM3Dq-mCherry fluorescence was localized mainly in the membrane of the neurons. The mCherry neurons were co-localized with AVP-like immunoreactive (LI) neurons, but not with oxytocin-LI neurons. The induction of Fos, which is the indicator for neuronal activity, was observed in approximately 90% of the AVP-LI neurons in the SON and PVN 90 min after intraperitoneal (i.p.) administration of CNO. Plasma AVP was significantly increased and food intake, water intake, and urine volume were significantly attenuated after i.p. administration of CNO. Although the detailed mechanism has unveiled, we demonstrated, for the first time, that activation of endogenous AVP neurons decreased food intake. This novel transgenic rat line may provide a revolutionary insight into the neuronal mechanism regarding central AVP system responsible for various kind of behaviours.
a b s t r a c tLamins are the major components of nuclear envelope architecture, being required for both the structural and informational roles of the nuclei. Mutations of lamins cause a spectrum of diseases in humans, including muscular dystrophy. We report here that the loss of the A-type lamin gene, lamin C in Drosophila resulted in pupal metamorphic lethality caused by tendon defects, matching the characteristics of human A-type lamin revealed by Emery-Dreifuss muscular dystrophy (EDMD). In tendon cells lacking lamin C activity, overall cell morphology was affected and organization of the spectraplakin family cytoskeletal protein Shortstop which is prominently expressed in tendon cells gradually disintegrated, notably around the nucleus and in a manner correlating well with the degradation of musculature. Furthermore, lamin C null mutants were efficiently rescued by restoring lamin C expression to shortstop-expressing cells, which include tendon cells but exclude skeletal muscle cells. Thus the critical function of A-type lamin C proteins in Drosophila musculature is to maintain proper function and morphology of tendon cells.
Oxytocin is involved in pain transmission, although the detailed mechanism is not fully understood. Here, we generate a transgenic rat line that expresses human muscarinic acetylcholine receptors (hM3Dq) and mCherry in oxytocin neurons. We report that clozapine-N-oxide (CNO) treatment of our oxytocin-hM3Dq-mCherry rats exclusively activates oxytocin neurons within the supraoptic and paraventricular nuclei, leading to activation of neurons in the locus coeruleus (LC) and dorsal raphe nucleus (DR), and differential gene expression in GABA-ergic neurons in the L5 spinal dorsal horn. Hyperalgesia, which is robustly exacerbated in experimental pain models, is significantly attenuated after CNO injection. The analgesic effects of CNO are ablated by co-treatment with oxytocin receptor antagonist. Endogenous oxytocin also exerts anti-inflammatory effects via activation of the hypothalamus-pituitary-adrenal axis. Moreover, inhibition of mast cell degranulation is found to be involved in the response. Taken together, our results suggest that oxytocin may exert anti-nociceptive and anti-inflammatory effects via both neuronal and humoral pathways.
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