Thermoregulatory responses elicited by microinjection of l-glutamate and its interaction with thermogenic effects of GABA and prostaglandin E2 in the preoptic area

Differences in carbachol dose, pain condition, and sex following lateral hypothalamic stimulation

“…More recent studies stress the role of the preoptic, paraventricular and dorsomedial hypothalamic areas in temperature control (Osaka, 2012, 2009, 2004; Morrison and Nakamura, 2011; Nakamura, 2011; de Menezes et al, 2009; Nakamura and Morrison, 2007; Nagashima et al, 2000). However, orexin-containing neurons in the LH perifornical area are now known to affect brown fat tissue (BAT) thermogenesis (Tupone et al, 2011; Richard, 2007; Oldfield et al, 2002), but only when body temperature is maintained below 37° (Morrison et al, 2012; Tupone et al, 2011).…”

Central Nervous System Regulation of Brown Adipose Tissue

“…3Cb) (242,243). Similarly, glutamatergic stimulation of MnPO neurons evokes increases in BAT SNA and BAT thermogenesis (242), or the increases in oxygen consumption that indirectly indicates BAT activation (268), that are similar to cold-defensive BAT responses. That the POA subregion receiving thermosensory cold signals is predominantly within the MnPO is supported by the findings that the projections from LPBel neurons activated by skin cooling terminate mainly in a median part of the POA (243) and that glutamatergic stimulation or disinhibition of the MnPO with nanoinjections of NMDA or bicuculline, respectively, evokes physiological responses mimicking cold-defensive responses (Figs.…”

Hypoxia-induced hypothermia mediated by the glutamatergic transmission in the lateral preoptic area

“…Consistent with these reports, T c decreased during the hypoxic ventilation without changes in T s , suggesting inhibition of heat production without heat loss response during this period. However, although activation of the lateral POA with glutamate reduces the baseline VO 2 and heart rate (Osaka, 2012), blockade of the glutamatergic transmission in the lateral POA with kynurenic acid did not affect the hypoxic ventilation-induced changes in VCO 2 and the decreases in VO 2 and heart rate evoked by the microinjection of NA into the rostromedial POA. These results may indicate that the glutamatergic mechanism in the lateral POA did not play any role in the suppression of thermogenesis during hypoxia, though it might be involved in the inhibition of thermogenesis in other situations, such as in a warm environment or during sleep (Glotzbach and Heller, 1976;Rechtschaffen et al, 1989).…”

“…Microinjection of glutamate elicits hypothermic responses in a widespread zone in the lateral POA and its vicinity (Osaka, 2012). Accordingly, a volume of 200 nl of kynurenic acid was microinjected into four locations (i.e., rostrolateral and centrolateral POA, bilaterally) to effectively block the glutamatergic transmission in this glutamate-responsive, hypothermiainducing zone.…”

“…Microinjection of the excitatory amino acid L-glutamate into the border between the medial and lateral POA has been shown to elicit heat-loss responses (Zhang et al, 1995). In the accompanying paper (Osaka, 2012), it was shown that the activation of the lateral POA, but not that of the medial POA, by microinjection of glutamate elicits heat loss and hypothermia. Therefore, I examined the hypothesis that the NA-and NO-sensitive site in the rostromedial POA activates the glutamatergic transmission in the lateral POA to mediate hypoxiainduced hypothermia.…”