Biomedical subjects

Shoichi Watanabe

Publications and source records attributed to Shoichi Watanabe.

8 recordsLinked to original sources

PubMed2005

First episodes of behavioral symptoms in Alzheimer's disease patients at age 90 and over, and early-onset Alzheimer's disease: comparison with senile dementia of Alzheimer's type.

We evaluated dementia symptoms to clarify the character of dementia with Alzheimer's disease (AD) observed in the oldest old patients and that of dementia with early-onset AD. Subjects were consecutive AD inpatients admitted for the first time at age of 90 years and over because of behavioral symptoms (demented nonagenarian group: D90G; n=18) and those with 24 consecutive inpatients with AD with early-onset (EOG). The Gottfries, Brane and Steen's scale and the Dementia Behavior Disturbance scale were used to evaluate the symptoms and troublesome behaviors. The scores of these scales in D90G and in EOG were compared with those of 26 sex distribution-, severity of dementia-, and disease duration-matched inpatients with AD with late-onset (LOG). Compared with LOG, wakefulness was more impaired and waking up at night was more frequent in D90G, while memory, orientation and inappropriate behaviors were more severe in EOG. These results suggest that the clinical features of dementia in EOG were quantitatively different from those of LOG. In contrast, the clinical feature of dementia of D90G were sleep-wake pattern disturbance and were qualitatively different from those of LOG.

Age of Onset↗

PubMed2004

Central stresscopin modulates cardiovascular function through the adrenal medulla in conscious rats.

Stresscopin (SCP or urocortin III), a member of the corticotropin-releasing factor (CRF) neuropeptide family, is a high-affinity ligand for the type 2 CRF receptor (CRF(2)). When administered peripherally, SCP suppresses food intake, delays gastric emptying and decreases heat-induced edema. Central administration of CRF produces marked hypertension and increased plasma catecholamine. However, the effects of SCP on the cardiovascular system are unknown. Thus, the present study compared the effects of intracerebroventricular (i.c.v.) administration of CRF and SCP on cardiovascular function. Central administration of SCP (0.05 or 0.5 nmol) elicited transient increases in mean arterial blood pressure (MABP) and heart rate (HR), and the higher dose of SCP (0.5 nmol) resulted in increased plasma epinephrine. In contrast, central administration of CRF provoked long-lasting increases in MABP, HR and plasma catecholamine levels (norepinephrine and epinephrine). Intravenously administered CRF and SCP (0.5 nmol) did not elicit significant changes in MABP and HR. Therefore, these data suggest that centrally administered SCP modulates cardiovascular function, likely through the sympatho-adrenal-medullary (SAM) system.

Adrenal Medulla↗

PubMed2004

The alpha 1D-adrenergic receptor modulates cardiovascular and drinking responses to central salt loading in mice.

To characterize the involvement of specific alpha(1)-adrenergic receptor (alpha(1)-AR) subtypes in hypertension, parameters related to central salt- or angiotensin II (ANG II)-induced hypertension were investigated in alpha(1D)-AR-deficient mice (knockout). Baseline daily water intake and food intake were larger in alpha(1D)(-/-) mice than in alpha(1D)(+/+) mice. Intracerebroventricular (i.c.v.) administration of NaCl (0.67 M NaCl, 1 microl) elicited smaller increases in mean arterial blood pressure (MABP), heart rate, and water intake in alpha(1D)(-/-) mice than it did in alpha(1D)(+/+) mice. I.c.v. administration of ANG II (10 pmol) resulted in increases in MABP and water intake that were similar in alpha(1D)(-/-) mice and alpha(1D)(+/+) mice. These results suggest that alpha(1D)-AR is, at least in part, involved in central salt-induced but not ANG II-induced hypertension and water intake.

Angiotensin II↗

PubMed2004

Effect of hypertonic saline on rat hypothalamic paraventricular nucleus magnocellular neurons in vitro.

The effect of hypertonic saline on rat hypothalamic paraventricular nucleus (PVN) magnocellular neurons was examined using a whole-cell patch-clamp technique. Under a current-clamp, 58/68 of magnocellular neurons were depolarized by hypertonic stimulation. Under a voltage-clamp, hypertonic saline produced an inward current via increased non-selective cationic conductance and shifting of the reversal potential to more positive values. Furthermore, hypertonic saline even without a change in osmolality increased spontaneous excitatory postsynaptic currents (sEPSCs). A bath application of CNQX almost completely blocked EPSCs. Extracellular application of gadolinium blocked the hypertonic saline- and mannitol-induced response. These results suggest that PVN magnocellular neurons are responsive to osmolality and Na+ concentrations. Hypertonic saline excited PVN magnocellular neurons via osmo-reception, Na+ -detection, and excitatory glutamatergic synaptic input.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

PubMed2004

Single-unit activity of paraventricular nucleus neurons in response to intero- and exteroceptive stressors in conscious, freely moving rats.

Extracellular recordings of 114 neurons in the hypothalamic paraventricular nucleus (PVN) of conscious, freely moving male rats were performed using a movable electrode system. Single-unit activities were examined for their spontaneous firing patterns and responses to intero- and exteroceptive stressors, including disturbance in arterial blood pressure, water deprivation, air-jet stimulation, and systemic administration of cholecystokinin-8 (CCK). PVN neurons were assigned to one of two groups on the basis of their spontaneous firing patterns: phasic (n=29) and non-phasic (n=85). Intravenous (i.v.) administration of phenylephrine (8 microg/kg) resulted in the inhibition of a greater percentage of phasic-type (88.9%; 24/27) than non-phasic-type neurons (14.9%; 11/74). Most phasic-type neurons showed excitation in response to i.v. administration of sodium nitroprusside (20 microg/kg, 66.7%; 18/27) and water deprivation (15 h, 77.8%; 7/9) when compared to non-phasic-type neurons. Conversely, a greater number of non-phasic-type neurons showed excitation in response to air-jet stimulation (5 l/min, 10 s, 29.0%; 20/69) and to i.v. administration of CCK (5 microg/kg, 24.5%; 11/45) when compared to phasic-type neurons. However, most non-phasic-type neurons that demonstrated excitation in response to i.v. administration of CCK (88.9%; 8/9) did not respond to air-jet stimulation. The present study indicated that phasically firing neurons recorded from the PVN in conscious, freely moving rats are putative vasopressin-secreting neurons on the basis of their responses to intero- and exteroceptive stressors. These data contribute to our understanding of local neural mechanisms within the PVN that are responsible for stress responses in conscious rats.

Action Potentials↗

PubMed2003

Enhanced effects of central angiotensin II on cardiovascular and drinking responses in inbred polydipsic (STR/N) mice.

STR/N, an inbred strain of mice, is known to exhibit extreme polydipsia and polyuria. The objective of this study was to investigate the possible reasons for polydipsia. First, comparisons were made between STR/N mice and control mice from the Institute of Cancer Research (ICR) concerning daily drinking, urinary excretion, and basal cardiovascular function. Then, since angiotensin II (ANG II) is a potent stimulus for drinking behavior, we investigated the effects of intracerebroventricular (i.c.v.) administration of ANG II on cardiovascular and water intake responses. Daily water intake, food intake, urinary volume, and urinary electrolytes (Na and K) excretion were larger in STR/N mice than in ICR mice, and the basal blood pressure was significantly lower in STR/N mice than in ICR mice. The i.c.v. administration of ANG II (10 pmol/per mouse) resulted in increased mean arterial blood pressure (MAP) and water intake in both STR/N and ICR mice, but the changes in MAP were significantly larger in STR/N mice than in ICR mice. These results suggest that polydipsia in STR/N mice is at least partially attributable to high sensitivity of central ANG II receptors and low MAP.

Angiotensin II↗

PubMed2002

Alterations of thermoregulation in women with hyperemesis gravidarum.

We investigated the thermoregulatory alterations to coldness in hyperemesis gravidarum. In pregnant women with hyperemesis (n=22), thermographic measurements for skin temperature and heat dissipation from the back were made during immersions of hands in 15 degrees C water for 50 s. A thermogenic ratio (TR) was calculated as (A-B)/B, where A and B represent the rate of heat dissipation (Cal/hr) from the interscapular and the whole back area, respectively. Simultaneously, changes in serum nonesterified fatty acids (NEFAs) were measured in response to the stimulus. A comparison was made between the women with and without hyperemesis (n=13). Skin temperature did not respond to slight cold stimulus. However, TR increased rapidly and kept increasing (P<0.01) and NEFAs increased (P<0.05) only in subjects with fasting hyperemesis. Increase in TR was closely associated with that of NEFAs (P<0.05) and weight loss. Characteristic thermoregulatory response is found in the interscapular skin region of hyperemesis gravidarum. This may be caused by elevated lipolytic activity associated with interscapular region in undernourished pregnant women.

Adult↗

PubMed2002

The current perception thresholds in normal pregnancy.

The purpose of this study was to evaluate a quantitative analysis of the nociceptive threshold, using the current perception threshold (CPT), in women with normal pregnancies and to assess the relationship between nociceptive thresholds and ovarian sex steroids. The subjects consisted of 10 women with singleton pregnancies and 14 age-matched healthy female volunteers. The CPTs (5,250, and 2,000 Hz) of the dominant ankle section were determined with a Neurometer CPT/C (Neurotron, Baltimore, MD). Blood samples were collected after these examinations, and the total 17beta-estradiol (E(2)) and progesterone concentrations in sera were measured. The present findings clearly indicated that the CPTs at 2,000 Hz in women at term in normal pregnancies were significantly higher than those in nonpregnant women (p<0.05). At 5 and 250 Hz, there was no significant difference between pregnant and nonpregnant women. While there was also no significant correlation between CPT and E(2), and progesterone, there was significant correlation between CPT and the ratio of 17 beta-estradiol/progesterone (E(2)/P) at 2,000 Hz (p<0.05, r=0.67). We suggest from these data that changes in pressure sensitivity occur at term in pregnancy, and that other factors, possibly stimulated by both E(2) and progesterone, may play an important role in this change.

Adult↗