Satoru Shimamune

Subfornical organ efferents enhance extracellular noradrenaline concentrations in the median preoptic area in rats.

The present study was carried out to examine whether angiotensinergic pathways from the subfornical organ (SFO) regulate the noradrenergic system in the median preoptic nucleus (MnPO). Intracerebral microdialysis techniques were used to quantify the extracellular concentration of noradrenaline (NA) in the MnPO area. In urethane-anesthetized male rats, electrical stimulation (5-20 Hz, 0.6 mA) of the SFO significantly increased the NA concentration in the MnPO area, and the increase was significantly diminished by pretreatment with the angiotensin II (ANG II) antagonist saralasin (Sar; 5 microg), into the third ventricle (3V). Injections of ANG II (5 microg) into the 3V significantly enhanced NA release in the MnPO area. The data imply that the angiotensinergic pathways from the SFO to the MnPO may act to enhance NA release in the MnPO area.

Ascending pathways from the nucleus of the solitary tract to the subfornical organ in the rat

Electrical stimulation of the nucleus of the solitary tract (NTS) produced orthodromic excitation (n = 28, 15%) and inhibition (n = 6, 4%) of the activity of neurons in the subfornical organ (SFO) in male rats under urethane anesthesia. Almost all (n = 26) of the excitatory responses (n = 28) were blocked by microiontophoretically applied phentolamine, an alpha-adrenergic antagonist, but not by timolol, a beta-adrenergic antagonist. In contrast, the inhibitory response of all the neurons (n = 6) tested was not affected by either phentolamine or timolol. Approximately two-third (n = 19) of SFO neurons that demonstrated the excitatory response to NTS stimulation exhibited an increase in neuronal activity in response to hemorrhage (10 ml/kg b.w.t.). Hemorrhage did not cause any change in the activity of all the neurons that demonstrated the inhibitory response to NTS stimulation. These results suggest that the excitatory pathways from the NTS to the SFO may transmit the peripheral baroreceptor information through alpha-adrenoreceptor mechanisms.

Effects of grammar instruction and fluency training on the learning of the and a by native speakers of japanese

In a computer-assisted sentence completion task, the effects of grammar instruction and fluency training on learning the use of the definite and indefinite articles of English were examined. Forty-eight native Japanese-speaking students were assigned to four groups: with grammar/accuracy (G/A), without grammar/accuracy (N/A), with grammar/fluency (G/F), and without grammar/fluency (N/F). In the G/A and N/A groups, training continued until performance reached 100% accuracy (accuracy criterion). In the G/F and N/F groups, training continued until 100% accuracy was reached and the correct responses were made at a high speed (fluency criterion). Grammar instruction was given to participants in the G/A and G/F groups but not to those in the N/A and N/F groups. Generalization to new sentences was tested immediately after reaching the required criterion. High levels of generalization occurred, regardless of the type of mastery criterion and whether the grammar instruction was given. Retention tests were conducted 4, 6, and 8 weeks after training. Fluency training effectively improved retention of the performance attained without the grammar instruction. This effect was diminished when grammar instruction was given during training. Learning grammatical rules was not necessary for the generalized use of appropriate definite and indefinite articles or for the maintenance of the performance attained through fluency training.

A1 noradrenergic modulation of AV3V inputs to PVN neurosecretory cells

PHASICALLY active neurosecretory neurons in the paraventricular nucleus (PVN) of urethane-anesthetized rats displayed orthodromic excitation, inhibition or no response following electrical stimulation of the anteroventral third ventricle (AV3V) region, and exhibited orthodromic excitation or no response following electrical stimulation of the A1 noradrenergic region of the ventrolateral medulla. Of the 14 neurons that responded to both the stimuli, A1 region stimulation at the subthreshold current significantly enhanced the excitation induced by AV3V region stimulation, and the enhancement was abolished by iontophoretically applied phentolamine, an α-adrenoceptor antagonist, but not by timolol, a β-adrenoceptor antagonist. These results suggest that A1 noradrenergic projections may act to potentiate the excitatory inputs from the AV3V region to vasopressinergic PVN neurons through α-adrenoceptor mechanisms.

Angiotensinergic modulation of osmotic activation of neurosecretory neurons.

EXTRACELLULAR recordings were obtained from 34 phasically active neurosecretory cells in the hypothalamic paraventricular nucleus (PVN) of male rats under urethane anesthesia. Intracarotid injections of hypertonic saline (0.2 M NaCl solution, 0.05 ml) caused an increase in neuronal activity of 27 PVN cells. Pretreatment with saralasin (Sar, 10−10M), a specific angiotensin II (ANG II) antagonist, into the median preoptic nucleus (MnPO) diminished the excitatory response to the osmotic stimulation in 13 of 17 cells tested. Pretreatment with Sar in the vicinity of the MnPO or the third ventricle did not cause a marked change. These results suggest that the ANGergic system in the MnPO could contribute to the mechanism of osmotic activation of PVN neurosecretory cells.

Effects of Performance‐Based Pay Systems on Quantity and Quality in Computer Programming

This experiment was conducted to investigate the effects of quality-contingent pay systems on quantity and quality. Three computer science students were paid to create simple computer programs across 25 sessions. A multiple-baseline across subjects design was used to compare the effects of three kinds of pay systems; pay-for-hour, pay-for-quantity, and pay-for-quality systems. The quantity was higher when pay was based on the quantity of the programs produced, and the quality was highest when pay was based on the quality of the programs. The production cost including quality inspection costs was highest when pay was based on the time worked.

612 Cholecystokininergic regulation of dopaminergic system in the rat posterior nucleus accumbens

The present study was carried out to clarify the action of cholecystokinin (CCK) on the dopaminergic system in the rat posterior nucleus accumbens (PNAc). The first experiment investigated the effects of microinjection of sulfated-CCK octapeptide (CCK-SS, 0.1 pg/kg) into the PNAc on dopamine (DA) turnover in the region of the injection site in awake rats. Microdialysis was utilized to quantify the extracellular concentrations of DA its major metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). CCK-8S injected into the PNAc caused an increase in DOPAC and HVA concentrations in the injection site, but did not affect the DA level. Similar injections of vehicle (1% NaHC03 solution, 0.1 rl/kg) did not have an effect. The second experiment examined the effects of microiontophoretic application of CCK-8S on the activity of PNAc neurons in rats treated with 6-hydroxydopamine (6-OHDA, 0.25 pg/kg) or vehicle (distilled water containing 0.2 mg/ml ascorbic acid, 0.5 ml/kg) in the poiterior part of PNAc, and intact rats under urethane anesthesia. The ratio of PNAc neurons that demonstrated an increased excitability in response to CCK-8S applied iontophoretically was markedly smaller in the 6-OHDA rats (11% and 5%: excitatory and inhibitory neurons) than in the vehicle (36% and 5%) and intact (34%,‘and 6%) rats. These results suggest that CCK acts at DA terminals in the PNAc to regulate the excitability of PNAc neurons.

617 Cholecystokininergic modulation of ventral tegmental dopaminergic inputs to the posterior nucleus accumbens in rats

Our previous study demonstrated that bradykinin increased intracellular free calcium concentration ( [Ca”ji) via bradykinin 82 receptors in primary cultured trigeminal ganglion cells of guinea pig. In this study, to investigate the correlation between bradykinin B2 receptors and prostaglandin E(PGE) receptor subtypes, we examined the effect of PGE2, 17-phenyl-trinor PGE2(EPt receptor agonist) and butaprost(EP2 receptor agonist) on the increase of [Ca2*ji induced by bradykinrn in cultured TG cells. PGE2(5fi M), 17phenyl-trinor PGE2 (0.1-10~ M) and butaprost (O.l-10~ M) did not give any change in [Ca2+]i, but markedly enhanced the bradykinin-Induced increase of [Ca’*ji. Among of those three, 17-phenyl-trinor PGE2was most potent. These results suggest that both EPt and EP2 receptors are involved in modulating the nociceptive information induced by bradykinrn in primary sensory neurons.

2423 Activation of ascending pathways from the nucleus of the solitary tract to the subfornical organ by hemorrhage

Endothelin, a brain-vascular peptide, consists of three isopeptides (ET-l, ET-2 and ET-3) and has two types of receptors (ET-AR and ET-BR), Our previous immunohistochemical study showed that ET-AR exists in the catecholaminergic (CA) neurons in CNS, dopaminergic amacrine cells in retina, and postganglionic sympathetic nerve cells. To elucidate the relationship between ETs and CAs, we immunohistochemically analyzed rat adrenal medulla using antibodies to mature ETs, Big ET-I, Big ET-3 and ET-AR. The animals (Wistar rats weighing 180-250 grams) were sacrificed under anesthesia with sodium pentobarbital (50mgjkg b.wt., i.p.). Many nerve fibers containing Big ET-l were found in adrenal medulla, while no immunoreactivity for mature ETs and Big ET-3 is observed. Noradrenalin cells, which do not contain PNMT enzyme, were immunostained with ET-AR antibody. In these cells, Cat+ release from endogenous stores occurred by ET1 administration to primary culture of adrenal medulla in vitro . Because Big ET1 can be converted

2422 Responses of median preoptic neurons projecting to the hypothalamic paraventricular nucleus to osmotic stimulation in WKY and SHR

Endothelin, a brain-vascular peptide, consists of three isopeptides (ET-l, ET-2 and ET-3) and has two types of receptors (ET-AR and ET-BR), Our previous immunohistochemical study showed that ET-AR exists in the catecholaminergic (CA) neurons in CNS, dopaminergic amacrine cells in retina, and postganglionic sympathetic nerve cells. To elucidate the relationship between ETs and CAs, we immunohistochemically analyzed rat adrenal medulla using antibodies to mature ETs, Big ET-I, Big ET-3 and ET-AR. The animals (Wistar rats weighing 180-250 grams) were sacrificed under anesthesia with sodium pentobarbital (50mgjkg b.wt., i.p.). Many nerve fibers containing Big ET-l were found in adrenal medulla, while no immunoreactivity for mature ETs and Big ET-3 is observed. Noradrenalin cells, which do not contain PNMT enzyme, were immunostained with ET-AR antibody. In these cells, Cat+ release from endogenous stores occurred by ET1 administration to primary culture of adrenal medulla in vitro . Because Big ET1 can be converted