K Nagai et aL Autonomic Neuroscience:Basic and Clinical 185 (2014)29-35 今 Stimulation with GFO Stimulation with LVO WAT-SNA BAT-SNA ASNA RSNA GVNA Fig.1.Effects of olfactory stimulation with scent of grapefruit oil(GPO)and lavender oil(LVO)on the activities of sympathetic nerves innervating the white adipose tissue(WAT-SNA) (Shen et al 2005a.b),brown adipose tissue(BAT-SNA)(Tanida et aL 2008b).adrenal gland (ASNA)(Shen et al 2005a:Shen et aL,2005b)and renal sympathetic nerve(RSNA)(Tanida et al.,2005b.2006)and the activity of the parasympathetic nerve innervating the stomach(GVNA)(Shen et al,2005a.b).Representative trace data from recordings of autonomic nerve activities before and after olfactory stimulation with the grapefruit oil(GFO)and lavender oil (LVO)scents for 10 min.The upper bars indicate the 10-min stimulation period,the lower bars indicate 20 min and the vertical bars indicate electrical activity of 200 spikes/5 s. treatment with xylocaine or ZnSO4(Niijima and Nagai,2003:Shen et al.. of GFO was abolished by anosmic treatment with either xylocaine or 2005a:Tanida et al,2005b).These findings suggest that the scent of ZnSO(Tanida et al,2005b).These findings suggest that olfactory stim- GFO increases ASNA and RSNA. ulation with the scent of GFO suppresses GVNA. Increased ASNA enhances adrenaline secretion in mammals The suppressions of the efferent vagal nerves innervating the stom- (Ganong.2005).which elevates BP(Ganong,2005).The renal sympa- ach and intestine cause the inhibition of gut movements(peristaltic thetic nerve or post-ganglionic sympathetic nerve fibers that innervate movements),digestion and absorption(Ganong,2005).Therefore,it the renal vascular bed(Dibona,1982)are under the control of the med- was possible that the scent of GFO might reduce the appetite.Thus, ullary sympathetic premotoneurons in the central nervous system and the effect of GFO scent on appetite was examined in un-anesthetized also play an important role in modulating BP(Guynet et al.,1996;Sly rats.In this study,the scent stimulation of 0.01%water-suspension of et al.,1999).Olfactory stimulation with the scent of 1%water- GFO for 15 min a day 3 times per week for 6 weeks reduced food intake suspension of GFO increased BP in urethane-anesthetized rats (Tanida and body weight(Shen et al,2005a). et al,2005b),suggesting that the GFO-induced increase in ASNA and These findings suggest that the scent of a certain amount of GFO re- RSNA elevates BP.Moreover,olfactory stimulation with the scent of duces appetite and body weight through the decrease in GVNA and prob- 1%water-suspension of R-(+)-limonene increased ASNA(Shen et al. ably that in intestinal vagal nerve activity.With respect to this issue,it has 2005a)and RSNA (Tanida et al.,2005b)in urethane-anesthetized rats been reported that fresh grapefruit,grapefruit capsules or grapefruit juice and consistent with these results,olfactory stimulation with the scent are effective for reducing body weight in humans(Fujioka et al,2006) of 1%water-suspension of R-(+)-limonene increased BP in urethane Whether this weight reduction was caused by the loss of appetite and/ anesthetized rats(Tanidaet al.2005b).These findings suggest that lim- or metabolic changes,such as the enhancement of lipid degradation and onene is one of the active substances in GFO that causes an increase in utilization,due to olfactory stimulation with the scent of grapefruit or BP through its effects on ASNA and RSNA. other mechanisms must be examined in the future. Moreover,the authors examined the effect of olfactory stimulation 2.4.Effects on the vagal nerve innervating the stomach and appetite with the R-(+)-limonene on GVNA in urethane-anesthetized rats and found that the scent of 1%water-suspension of R-(+)-limonene sup- Olfactory stimulation with the scent of 1%water-suspension of pressed GVNA(Shen et al.,2005a;Tanida et al,2005a;)This result sug- GFO suppressed gastric vagal nerve activity (GVNA)in urethane- gests that limonene is at least one of the effective substances in GFO for anesthetized rats (Shen et al.,2005a;Tanida et al.,2005b).This effect its lowering action of GVNA.treatment with xylocaine or ZnSO4 (Niijima and Nagai, 2003; Shen et al., 2005a; Tanida et al., 2005b). These findings suggest that the scent of GFO increases ASNA and RSNA. Increased ASNA enhances adrenaline secretion in mammals (Ganong, 2005), which elevates BP (Ganong, 2005). The renal sympa￾thetic nerve or post-ganglionic sympathetic nerve fibers that innervate the renal vascular bed (Dibona, 1982) are under the control of the med￾ullary sympathetic premotoneurons in the central nervous system and also play an important role in modulating BP (Guynet et al., 1996; Sly et al., 1999). Olfactory stimulation with the scent of 1% water￾suspension of GFO increased BP in urethane-anesthetized rats (Tanida et al., 2005b), suggesting that the GFO-induced increase in ASNA and RSNA elevates BP. Moreover, olfactory stimulation with the scent of 1% water-suspension of R-(+)-limonene increased ASNA (Shen et al., 2005a) and RSNA (Tanida et al., 2005b) in urethane-anesthetized rats and consistent with these results, olfactory stimulation with the scent of 1% water-suspension of R-(+)-limonene increased BP in urethane￾anesthetized rats (Tanida et al., 2005b). These findings suggest that lim￾onene is one of the active substances in GFO that causes an increase in BP through its effects on ASNA and RSNA. 2.4. Effects on the vagal nerve innervating the stomach and appetite Olfactory stimulation with the scent of 1% water-suspension of GFO suppressed gastric vagal nerve activity (GVNA) in urethane￾anesthetized rats (Shen et al., 2005a; Tanida et al., 2005b). This effect of GFO was abolished by anosmic treatment with either xylocaine or ZnSO4 (Tanida et al., 2005b). These findings suggest that olfactory stim￾ulation with the scent of GFO suppresses GVNA. The suppressions of the efferent vagal nerves innervating the stom￾ach and intestine cause the inhibition of gut movements (peristaltic movements), digestion and absorption (Ganong, 2005). Therefore, it was possible that the scent of GFO might reduce the appetite. Thus, the effect of GFO scent on appetite was examined in un-anesthetized rats. In this study, the scent stimulation of 0.01% water-suspension of GFO for 15 min a day 3 times per week for 6 weeks reduced food intake and body weight (Shen et al., 2005a). These findings suggest that the scent of a certain amount of GFO re￾duces appetite and body weight through the decrease in GVNA and prob￾ably that in intestinal vagal nerve activity. With respect to this issue, it has been reported that fresh grapefruit, grapefruit capsules or grapefruit juice are effective for reducing body weight in humans (Fujioka et al., 2006). Whether this weight reduction was caused by the loss of appetite and/ or metabolic changes, such as the enhancement of lipid degradation and utilization, due to olfactory stimulation with the scent of grapefruit or other mechanisms must be examined in the future. Moreover, the authors examined the effect of olfactory stimulation with the R-(+)-limonene on GVNA in urethane-anesthetized rats and found that the scent of 1% water-suspension of R-(+)-limonene sup￾pressed GVNA (Shen et al., 2005a; Tanida et al., 2005a;). This result sug￾gests that limonene is at least one of the effective substances in GFO for its lowering action of GVNA. Stimulation with GFO Stimulation with LVO WAT-SNA BAT-SNA ASNA RSNA GVNA Fig. 1. Effects of olfactory stimulation with scent of grapefruit oil (GFO) and lavender oil (LVO) on the activities of sympathetic nerves innervating the white adipose tissue (WAT-SNA) (Shen et al., 2005a,b), brown adipose tissue (BAT-SNA) (Tanida et al., 2008b), adrenal gland (ASNA) (Shen et al., 2005a: Shen et al., 2005b) and renal sympathetic nerve (RSNA) (Tanida et al., 2005b, 2006) and the activity of the parasympathetic nerve innervating the stomach (GVNA) (Shen et al., 2005a,b). Representative trace data from recordings of autonomic nerve activities before and after olfactory stimulation with the grapefruit oil (GFO) and lavender oil (LVO) scents for 10 min. The upper bars indicate the 10-min stimulation period, the lower bars indicate 20 min and the vertical bars indicate electrical activity of 200 spikes/5 s. K. Nagai et al. / Autonomic Neuroscience: Basic and Clinical 185 (2014) 29–35 31