PYY3-36-HSA is a large molecule that does not penetrate the blood–brain barrier, and thus provides a useful tool to discriminate between the central (brain) and peripheral
actions of this peptide. PYY3-36-HSA induced significant reductions in food and body weight gain up to 24 h after administration. The anorectic effect of PYY3-36-HSA was delayed for 2 h in rats in which both AP and SFO were ablated, while lesion of either of these circumventricular organs in isolation did not influence the feeding responses to PYY3-36-HSA. The PYY3-36-HSA-induced anorectic effect was also reduced during the 3- to 6-h period following subdiaphragmatic vagotomy. Lesions of AP, SFO and AP/SFO as well as subdiaphragmatic vagotomy blunted PYY3-36-HSA-induced expression of c-fos Small Molecule Compound Library mRNA in specific brain structures including the bed nucleus of stria terminalis, central amygdala, lateral–external parabrachial nucleus and medial nucleus of the solitary tract. In addition, subdiaphragmatic vagotomy inhibited the neuronal activation induced by PYY3-36-HSA in AP and SFO. These findings suggest that the anorectic effect and brain neuronal activation induced by PYY3-36-HSA are dependent on integrity of AP, SFO and subdiaphragmatic vagus nerve. ”
“Striatal medium-sized CFTR modulator spiny neurons (MSSNs) receive glutamatergic inputs modulated presynaptically and postsynaptically by
dopamine. Mice expressing the gene for enhanced green fluorescent protein Selleckchem C225 as a reporter gene to identify MSSNs containing D1 or D2 receptor subtypes were used to examine dopamine modulation of spontaneous excitatory postsynaptic currents (sEPSCs) in slices and postsynaptic N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) currents in acutely isolated cells. The results demonstrated dopamine
receptor-specific modulation of sEPSCs. Dopamine and D1 agonists increased sEPSC frequency in D1 receptor-expressing MSSNs (D1 cells), whereas dopamine and D2 agonists decreased sEPSC frequency in D2 receptor-expressing MSSNs (D2 cells). These effects were fully (D1 cells) or partially (D2 cells) mediated through retrograde signaling via endocannabinoids. A cannabinoid 1 receptor (CB1R) agonist and a blocker of anandamide transporter prevented the D1 receptor-mediated increase in sEPSC frequency in D1 cells, whereas a CB1R antagonist partially blocked the decrease in sEPSC frequency in D2 cells. At the postsynaptic level, low concentrations of a D1 receptor agonist consistently increased NMDA and AMPA currents in acutely isolated D1 cells, whereas a D2 receptor agonist decreased these currents in acutely isolated D2 cells. These results show that both glutamate release and postsynaptic excitatory currents are regulated in opposite directions by activation of D1 or D2 receptors. The direction of this regulation is also specific to D1 and D2 cells.