“…Accordingly, the afferent and efferent limbs of the brain’s glucoregulatory system should be distinguishable from one another, with the afferent limb being comprised of neurons situated outside of, or with access across, the BBB and the efferent limb situated in areas behind the BBB, such as the VMN (by analogy to the organization of neurocircuits involved in thermoregulation). After all, changes in the activity of glucose-sensitive neurons in the VMN and elsewhere can potently influence both the plasma glucose level and the secretion of insulin and glucagon (via changes in autonomic output to liver and pancreas) (Fioramonti et al, 2017; Kang et al, 2006; Meek et al, 2016; Pozo and Claret, 2018; Zhou et al, 2018). Moreover, the activity of glucoregulatory neurons in the VMN comprising the efferent limb of the system is known to be influenced by ascending input from projections from the parabrachial nucleus (Flak et al, 2014; Garfield et al, 2014) (a brain area richly supplied with projections from the NTS).…”