Nami Someya

Blood flow responses in celiac and superior mesenteric arteries in the initial phase of digestion

Blood flow (BF) responses in the celiac artery (CA) and superior mesenteric artery (SMA) during and immediately after a meal are poorly understood. We characterized postprandial BF responses in these arteries in the initial phase of digestion. After a baseline measurement in the overnight fasting state, healthy subjects ingested solid food (300 kcal) and water ad libitum within 5 min (4.6 +/- 0.2 min, means +/- SE), and then rested for 60 min in the postprandial state. Mean blood velocities (MBVs) in CA (n = 7) and SMA (n = 9) and mean arterial pressure (MAP) were measured throughout the procedure. The MAP was divided by the MBV to yield the resistance index (RI). The MBV in CA and SMA started increasing within a minute after beginning the meal. The MBV in CA rapidly reached its peak increase (60 +/- 8% change from baseline) at 5 +/- 1 min after the start of the meal, whereas the MBV in SMA gradually reached its peak increase (134 +/- 14%) at 41 +/- 4 min after the start of the meal, reflecting a decrease in the RI for both CA and SMA. These findings suggested an earlier increase in CA and SMA MBV, implying that the increase of BF in some parts of the small intestine precedes the arrival of chyme.

Vascular responses to fear-induced stress in humans

The information about the effect of mental activities on detailed cardiovascular responses is limited, though strong and chronic psychological stressors are risk factors of cardiovascular morbidity and mortality in humans. The responses of vascular resistance (VR) during fear-induced stress was studied by measuring the mean arterial pressure (MAP), heart rate (HR), skin blood flow in the index finger and forehead, limb blood flow in the calf and forearm, and blood flow in the renal and superior mesenteric arteries before, during, and after a period of induced fear. After 2 min of rest, baseline data were acquired from eight subjects, after which they watched a 3-min video that was considered to be frightening. Minute-by-minute data were calculated. The MAP was divided by the blood flow to attain the VR. While a clear steady state was not evident in the stress-induced vascular response, stress significantly increased the MAP and HR (e.g., by 10+/-3 mm Hg and 8+/-3 bpm, respectively, at the 2nd min; mean+/-SEM), and the VR of the forearm and finger skin (e.g., by 80+/-26% and 79+/-28%, respectively, at the 2nd min). The VR increased slightly in the calf and visceral arteries but not in the forehead throughout the stimulation. The variables returned to baseline levels by the 1st min after cessation of the fearful stimulation. These results suggest that fear-induced stress causes vasoconstriction in the forearm and finger.

Vasoconstriction and blood flow responses in visceral arteries to mental task in humans

The vascular responses to mental task in visceral arteries in humans have not been elucidated. We observed the responses in the renal (RA) and superior mesenteric (SMA) arteries to mental stress, using simultaneous pulsed and echo Doppler ultrasound flowmetry. Nine healthy females performed a computerized colour word conflict test (CWT) for 3 min. The mean blood velocity (MBV) in the right RA and SMA, heart rate (HR) and blood pressure were measured. The mean arterial pressure (MAP) was divided by the flow velocity to assess the vascular resistance (VR). The CWT significantly increased the MAP, HR and VR in both arteries from the first minute. During the CWT, flow in the RA decreased significantly at the third minute relative to baseline, while flow in the SMA showed no significant change from the first to the third minute. The degree of vasoconstriction in the RA bed was greater than that in the SMA bed. These results suggest that the mental task causes vasoconstriction in visceral arteries, and imply that it induces differential blood flow and vascular responses in visceral arteries.

Chewing and taste increase blood velocity in the celiac but not the superior mesenteric arteries

To investigate the role of chewing and taste in the meal-induced rapid increase in splanchnic blood flow, we compared the blood flow responses in the celiac artery (CA) and superior mesenteric artery (SMA) to chewing solid food with a chocolate taste (FOOD) and paraffin wax without taste (WAX). After 5 min of baseline measurement, 15 healthy subjects repeated chewing and expectorating the FOOD or WAX every 20 s for 4 min followed by 10 min of recovery measurement. We measured the mean blood velocity (MBV) in the CA and SMA. The baseline MBVs in the CA and SMA did not differ between the FOOD and WAX trials. The MBV in the CA was lower than baseline at the 1st min of chewing in both trials. It was higher than baseline at the 3rd min of FOOD chewing, whereas it did not increase during and after WAX chewing. The MBV in the CA was higher in the FOOD trial than in the WAX trial at the 3rd min of chewing and thereafter. In contrast, the MBV in the SMA did not change throughout the protocols. These results suggest that the taste of food plays a role in meal-induced hyperemia in the CA but not the SMA.

The limited effect of breathing frequency on blood velocity measurements in renal and superior mesenteric arteries.

Breathing including abdominal movement could affect the blood velocity (BV) measurement in the visceral arteries. The present study investigated the effect of breathing frequency on the renal artery (RA) and superior mesenteric artery (SMA) BV measurements. We measured mean arterial pressure (MAP), heart rate (HR) and BV in the RA and SMA using the Doppler technique at different respiratory frequencies. Nine subjects performed breath-holding (<40 s), and spontaneous and controlled breathings at a constant rate of 12, 15 and 20 breaths min(-1). The breathing frequency did not significantly affect the BV in either artery. The BVs at these frequencies were not significantly different from those during spontaneous breathing and breath-holding. There were no significant differences in MAP and HR among trials. This result suggests that the effect of breathing frequency adopted in this study could be neglected in the RA and SMA measurements.

Effect of preceding exercise on cerebral and splanchnic vascular responses to mental task

BackgroundTo investigate the effect of preceding acute exercise on the peripheral vascular response to a mental task, we measured splanchnic and cerebral blood flow responses to performing a mental task after exercise and resting.MethodsIn the exercise trial, 11 males exercised for 30 min on a cycle ergometer with a workload set at 70% of the age-predicted maximal heart rate for each individual. After a 15-min recovery period, the subjects rested for 5 min for pre-task baseline measurement and then performed mental arithmetic for 5 min followed by 5 min of post-task measurement. In the resting trial, they rested for 45 min and pre-task baseline data was obtained for 5 min. Then mental arithmetic was performed for 5 min followed by post-task measurement. We measured the mean blood velocity in the middle cerebral artery and superior mesenteric artery and the mean arterial pressure.ResultsMean arterial pressure and mean blood velocity in the middle cerebral artery were significantly higher than the baseline during mental arithmetic in both exercise and resting trials. Mean blood velocity in the middle cerebral artery during mental arithmetic was greater in the control trial than the exercise trial. Mean blood velocity in the superior mesenteric artery showed no significant change during mental arithmetic from baseline in both trials.ConclusionThese results suggest that acute exercise can moderate the increase in cerebral blood flow induced by a mental task.

Self-selection of anti-depressant herbal medicine depends on internal and external conditions in rats

the open arms in the EPM was negatively correlated with food intake during recovery period in the TPF-r. This result suggests that the rat showing higher anxiety could consume more food after mild stress. Though the significant difference was not observed in the locomotor activity among the TPF-r, TP, and CF, the TPF-n showed shorter distance moved in the open field after the tail pinch compared to the other groups. This result implies that the expression of eating in stress condition could affect consecutive behaviors. Research fund: Grant-in-Aid for JSPS Fellows (22.6878).

Low dose neonatal exposure to bisphenol A affects emotional and social functions in a sex dependent manner in rats

P3-o18 Behavioral role of thalamostriatal neural pathway in conditional discrimination paradigm Shigeki Kato 1 , Masahito Kuramochi 1,2, Kenta Kobayashi 1, Ryoji Fukabori 1, Motokazu Uchigashima 3, Masahiko Watanabe 3, Yuji Tsutsui 4, Kazuto Kobayashi 1,2 1 Dept. Mol. Genet., Fukushima Med. Univ., Fukushima, Japan 2 CREST/JST, Kawaguchi, Japan 3 Dept. Anat., Hokkaido Univ., Sapporo, Japan 4 Div. Human Support Sys., Fukushima Univ., Fukushima, Japan

Social interaction modulated by nasal application of testosterone in the rhesus monkey

Areas in and around superior temporal sulcus (STS) are thought to be important to social behavior (e.g., recognizing other’s action and intention). Although new-world monkey marmosets have strong pro-social nature, data related connection of STS is scanty. We performed retrograde tracer (CTB-Alexa 488 or 555) injection around superior temporal cortex of the marmosets. So far, we have made three injections into dorsal and ventral parts of middle STS and dorsal part of caudal STS. We found each injection resulted in unique input pattern, like macaque monkey (Selzer and Pandya, 1994). But, in general, areas around STS receive strong projection form multiple sources (insular, parietal cortex, frontal and occipital cortices), as expected as its multi-modal nature. Based on these results, we will discuss the subdivision of the marmoset areas around STS, by combining with electrophysiology and cytoarchitectures. Research fund: KAKENHI (22300104).