Influence of leptin and GABAB-receptor agonist and antagonist on neurons of the hypothalamic infundibular nucleus in the chicken

Abstract

In birds and mammals, the neuroendocrine regulation of energy balance is conserved in many aspects. Despite significant similarities between the two groups, differences in the regulatory mechanisms were detected. The present study was performed to carry out investigations of the influence of human leptin and GABA-receptor agonist and antagonist on the firing rate of neurons of the Nucleus infundibuli hypothalami in brain slices from juvenile chickens. For the first time, we demonstrated a clear, dose-related change in the firing rate of hypothalamic neurons in juvenile chickens after the acute application of recombinant human leptin (1, 10, and 100 nM). All investigated neurons increased their subsequent firing rate. Application of GABA-receptor agonist baclofen (1 µM) blocked, while antagonist CGP 35348 (10 µM) increased the spontaneous neuronal activity. Simultaneous application of baclofen and leptin reduced the effect observed from single leptin application. This was not found after simultaneously application of leptin and CGP. Altogether, our results indicate that in bird brain slices, and exemplarily in those of the chicken, hypothalamic neurons show mammalian-like responsiveness after acute leptin and GABA application. GABA-mechanisms involved in GABA release play a likely important role in the leptin-mediated effects on NI neurons via functional leptin receptors.

Should I Lay or Should I Grow: Photoperiodic Versus Metabolic Cues in Chickens

“…Interestingly, LEP inhibited apoptosis, as indicated by the reduced expression of apoptotic markers within the ovary, along with the promotion of steroidogenesis and differentiation, supporting follicular development ( Sirotkin and Grossmann, 2007 ). Recent studies have also shown that chicken LEP increases the firing rate of neurons within the IN ( Bogatyrev et al, 2017 ), while reducing the expression of the glucocorticoid receptor in the brain ( Yuan et al, 2017 ). This suggests that LEP has the ability to influence signalling within this region of the brain.…”

Neuroendocrine response to GABA-B receptor agonism in alcohol-dependent individuals: Results from a combined outpatient and human laboratory experiment

“…Leptin receptors are widely expressed on GABAergic neurons, particularly in brain regions responsible for homeostatic (e.g., hypothalamus) and hedonic (e.g., ventral tegmental area) food intake (Fujikawa et al, 2013; Fulton et al, 2006; Ovesjo et al, 2001; Xu et al, 2012). Collectively, previous data show that leptin potentiates GABAergic neurotransmission to regulate consummatory behaviors (Bogatyrev et al, 2017; Guimond et al, 2014; Krolczyk et al, 2005; Xu et al, 2012; Zupancic and Mahajan, 2011). Peripheral concentrations of leptin are generally correlated with adipose tissue volume, and a 12-week trial with baclofen significantly reduced leptin levels in obese individuals (Arima and Oiso, 2010).…”