Acotiamide hydrochloride (Z-338), a novel prokinetic agent, restores delayed gastric emptying and feeding inhibition induced by restraint stress in rats.

Acotiamide hydrochloride (Z-338) is a member of new class prokinetic agents currently being developed for the treatment of functional dyspepsia (FD). DNA microarray analysis showed that acotiamide altered the expressions of stress-related genes such as gamma-aminobutyric acid (GABA) receptors, GABA transporters and neuromedin U (NmU) in the medulla oblongata or hypothalamus after administration of acotiamide. Therefore, effects of acotiamide on stress-related symptoms, delayed gastric emptying and feeding inhibition, in rats were examined. Acotiamide significantly improved both delayed gastric emptying and feeding inhibition in restraint stress-induced model, but did not affect both basal gastric emptying and feeding in intact rats, indicating that acotiamide exerted effects only on gastric emptying and feeding impaired by the stress. On the other hand, mosapride showed significant acceleration of gastric emptying in intact and restraint stress-induced model, and itopride showed no effect on restraint stress-induced delayed gastric emptying. In addition, gene expression of NmU increased by restraint stress was suppressed by administration of acotiamide, while acotiamide had no effect on delayed gastric emptying induced by an intracerebroventricular administration of NmU, suggesting that the suppressive effect of acotiamide on gene expression of NmU might be important to restore delayed gastric emptying or feeding inhibition induced by restraint stress. These findings suggest that acotiamide might play an important role in regulation of stress response. As stress is considered to be a major contributing factor in the development of FD, the observed effects may be relevant for symptom improvement in FD.

Effect of polaprezinc on impaired healing of chronic gastric ulcers in adjuvant-induced arthritic rats--role of insulin-like growth factors (IGF)-1.

Polaprezinc, N-(3-aminopropionyl)-L-histidinatozinc, has been shown to stimulate the production of insulin-like growth factor-1 (IGF-1) in mesenchymal cells, the polypeptide playing a role in the gastric epithelial wound repair. The present study was performed to examine the effect of polaprezinc on the impaired healing of chronic gastric ulcers in adjuvant-induced arthritic rats, in relation to IGF-1. Arthritis was induced in male Dark Agouti (DA) rats by a single injection of Freund's complete adjuvant (FCA), and the gastric ulcers were induced by thermal cauterization (70 degrees C for 30 sec) 7 days after FCA injection. Omeprazole (30 mg/kg) was administered p.o. once daily, while recombinant human IGF-1 (rhIGF-1) (30 micrograms/kg, s.c.) or polaprezinc (3-10 mg/kg, p.o.) was administered twice daily, starting from 3 days after ulceration for 14 days. The healing of gastric ulcers was significantly delayed in arthritic rats as compared to normal rats on day 10 and 17 following ulceration. The expression of IGF-1 mRNA was markedly increased in the ulcerated mucosa, but this response was apparently attenuated in arthritic rats. Repeated administration of polaprezinc accelerated the healing of gastric ulcers in both normal and arthritic rats, in a dose-dependent manner, and this effect was more pronounced in arthritic rats. Likewise, treatment with omeprazole also significantly promoted the healing of gastric ulcers in both normal and arthritic rats. On the other hand, rhIGF-1 significantly promoted the gastric ulcer healing in arthritic rats without any effect on that in normal rats. These results suggest that the impaired healing of chronic gastric ulcers in arthritic rats is, at least partly, accounted for by less expression of IGF-1, and the polaprezinc improves the delayed healing of gastric ulcers in arthritic rats, probably through an increase in IGF-1 production.

Effect of water extracts of Rhizopus delemar on the stimulus coupled responses of neutrophils and their modulation by various protein kinase inhibitors.

Human peripheral blood polymorphonuclear leukocytes were preincubated with water extracts from Rhizopus delemar. The water extracts significantly inhibited arachidonic acid induced superoxide generation, whereas enhanced superoxide generation induced by phorbol 12-myristate 13-acetate but not those induced by N-formyl-methionyl-leucyl-phenylalanine. Superoxide generation induced by water extracts was inhibited by staurosporine, an inhibitor of protein kinase C, and was enhanced by genistein, an inhibitor of tyrosine kinase. The water extracts incubated with phorbol 12-myristate 13-acetate markedly increased phosphorylation of serine residue of 28.5 kDa protein with time and the phosphorylation depended on the concentration of the water extracts, whereas the water extracts incubated with arachidonic acid decreased the phosphorylation of serine residue of 38 and 42 kDa proteins. The phosphorylation of 28.5 kDa protein induced by the water extracts was inhibited by staurosporine, an inhibitor of protein kinase C, but was not inhibited by genistein, an inhibitor of tyrosine kinase.

Influence of the electrical stimulation of the hypothalamus on adrenocortical steroidogenesis in hypophysectomized rats.

The electrical stimulation of the ventromedial hypothalamus (VMH), lateral hypothalamic area (LHA), periventricular arcuate nucleus (ARC), and posterior hypothalamus (PHY), on 14C transfer rates from 14C-1-acetate into adrenocortical steroids in adrenal slices of hypophysectomized rats were investigated. The 14C transfer rates into corticosterone and cortisol were increased by the stimulation of the VMH, ARC, and PHY, but decreased by the stimulation of the LHA. From these results, it might be suggested that these hypothalamic structures were involved in the regulation of adrenocortical steroidogenesis without participation of the pituitary.

Influence of electrical stimulation of the hypothalamus on ovarian steroidogenesis in hypophysectomized and adrenalectomized rats.

The effects of electrical stimulation of the lateral hypothalamic area (LHA), periventricular arcuate nucleus (ARC) and ventromedial hypothalamic nucleus (VMH) on the rates of 14C transfer from 14C-1 acetate into ovarian steroids in ovarian slices of hypophysectomized and adrenalectomized (H-A) rats were investigated. The 14C transfer rates into estrogen and 20 alpha-hydroxypregn-4-en-3-one (20 alpha-OH-P) were decreased by LHA stimulation. The stimulation of the ARC and VMH increased the rates of 14C transfer into estrogen, progesterone and 20 alpha-OH-P. From these results, it might be suggested that these hypothalamic structures were involved in the regulation of ovarian steroidogenesis without participation of the pituitary and adrenal.

Influence of lesions of the limbic-hypothalamic system on metabolic response of pyruvate to daily repeated immobilization stress in rabbits.

The pyruvate metabolic response to the 1st exposure (exposure on the 1st day) to immobilization stress (IMO) were considerably altered by lesions of the periventricular arcuate nucleus (ARC), ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). The pyruvate metabolic responses to IMO were completely abolished by seven times repetition of exposure to IMO in the rabbits with lesions of ARC and VMH; they were similar to sham-operated groups. In rabbits with lesions of ST and FX, the pyruvate metabolic responses to the 7th exposure (exposure on the 7th day) to IMO were almost the same as those after the 1st exposure to IMO, but these metabolic responses were completely abolished by the seven times repetition of exposure to IMO in the sham-operated animals. These results suggest that firstly the ARC, VMH, amygdala (AMYG)-ST system and dorsal hippocampus (HPC)-FX system are involved in the pyruvate metabolic responses to the 1st exposure to IMO, and secondly, that the AMYG-ST system and the HPC-FX system are involved in the disappearance process of pyruvate metabolic responses to IMO by the daily repetition of exposure to IMO.

Subfornical organ efferents influence the activity of median preoptic neurons projecting to the hypothalamic paraventricular nucleus in the rat.

Twelve neurons in the median preoptic nucleus were antidromically activated by electrical stimulation of the hypothalamic paraventricular nucleus in the rat. Electrical stimulation of the subfornical organ produced excitation (N = 7) or inhibition (N = 4) of the activity of these identified units. The activity of all identified units that were excited by stimulation of the subfornical organ was also excited by microiontophoretically applied angiotensin II whereas the remaining units were not affected. The excitatory responses of the identified units to subfornical organ stimulation or applied angiotension II were blocked by saralasin, an angiotensin II antagonist.

Ventrolateral medullary neurons projecting to the medial preoptic/anterior hypothalamic area through the medial forebrain bundle: an electrophysiological study in the rat.

A total of 152 ventrolateral medullary neurons was antidromically stimulated from both the medial preoptic/anterior hypothalamic area (MPOAH) and the medial forebrain bundle (MFB) in urethane anesthetized rats. These neurons were located primarily dorsal to the lateral reticular nucleus and could be readily classified in at least two groups, type I and type II cells on the basis of electrophysiological properties. The action potentials of type I cells had a shorter duration, and their conduction velocities ranged from 0.45 to 3.1 m/s. By contrast, type II cells, most predominantly observed, were characterized by a longer duration and an unusual shape of their action potential, and the antidromic propagation into the somatodendritic complex was often blocked. The conduction velocity (mean = 0.21 m/s) and absolute refractory period (mean = 2.63 ms) of type II cells are consistent with them having fine non-myelinated axons. Injection of 6-hydroxydopamine (6-OHDA), but not 5,7-dihydroxytryptamine, directly into the MFB blocked antidromic responses of 57% of type II cells tested. The residual type II cells whose antidromic responses were not affected by 6-OHDA were located significantly rostral to the 6-OHDA sensitive cells. Neither antidromic response of type I cells tested, on the other hand, was affected by 6-OHDA. The majority of type I cells were dramatically activated by noxious pinches of the tail, whereas the noxious stimuli produced no detectable change in the firing of type II cells. These data demonstrate that ventrolateral medullary neurons projecting to the MPOAH through the MFB are comprised of at least three distinct populations: 6-OHDA resistant fast conducting cells with somatic afferents, 6-OHDA sensitive and resistant slow conducting cells.

Influence of lesions in the limbic-hypothalamic system on metabolic responses of pyruvate to daily repeated heat exposures in rabbits.

The effects of lesions of the limbic-hypothalamic structures on the pyruvate metabolic responses to daily repeated heat exposures in the liver of rabbits have been investigated. The experimental results were as follows: 1. The pyruvate metabolic responses to the 1st heat exposure (heat exposure on the 1st day) were altered by lesions of periventricular arcuate nucleus (ARC), ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). 2. The pyruvate metabolic responses to heat exposure were completely abolished by the ten times repetition of daily heat exposures in rabbits with lesions of ARC, VMH and ST, as same as in each sham-operated group. 3. In rabbits with FX lesions, the pyruvate metabolic responses to heat exposure remained even after the ten times repetition of daily heat exposures. 4. From these results, it might be suggested that ARC, VMH, amygdala (AMYG)-ST system and dorsal hippocampus (HPC)-FX system played a certain role in the mechanisms of pyruvate metabolic responses to the 1st heat exposure, but only the HPC-FX system participated in the process of pyruvate metabolic adaptation to daily repeated heat exposures.

Influence of lesions in the limbic-hypothalamic system on metabolic response of pyruvate to daily repeated cold exposure in rabbits.

The effects of lesions of the limbic-hypothalamic structures on the pyruvate metabolic responses to daily repeated cold exposures in the liver of rabbits have been investigated. The experimental results were as follows: The metabolic pattern of pyruvate and the pyruvate metabolic responses to the 1st cold exposure (cold exposure on the 1st day) were altered by lesions of periventricular arcuate nucleus (ARC), ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). The pyruvate metabolic responses to cold exposure were completely abolished by seven times repetition of daily cold exposures in rabbits with lesions of ARC, VMH and FX, as well as in each sham-operated group. In rabbits with ST lesions, the pyruvate metabolic responses to cold exposure remained even after the seven times repetition of daily cold exposures. From these results, it might be suggested that the ARC, VMH, amygdala (AMYG)-ST system and dorsal hippocampus (HPC)-FX system played a certain role in the metabolic regulation of pyruvate and in the mechanisms of pyruvate metabolic responses to the 1st cold exposure, but that only the AMYG-ST system participated in the process of pyruvate metabolic adaptation to daily repeated cold exposures.

Influence of lesions in the limbic-hypothalamic system on metabolic response of acetate to daily repeated immobilization stress.

The effects of lesions in the basal medial hypothalamus and limbic structure on the acetate metabolic responses to daily repeated exposure to immobilization stress in the liver of rabbits have been investigated. The experimental results were as follows: (1) The acetate metabolic response to the 1st exposure to immobilization stress (exposure on the 1st day) were considerably altered by lesions in the periventricular arcuate nucleus (ARC) ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). (2) The acetate metabolic responses to immobilization stress were completely abolished by seven times repetition of immobilization stress in the rabbits with lesions in ARC, VMH and FX; they were similar to sham-operated groups. (3) In rabbits with ST lesions, the acetate metabolic responses to the 7th exposure (exposure on the 7th day) to immobilization stress were exactly the same as those after the 1st exposure of immobilization stress, but these metabolic responses were completely abolished by the seven times repetition of exposure in the sham-operated animals. (4) These results suggest that firstly, the ARC, VMH, amygdala(AMYG)-ST system and dorsal hippocampus(HPC)-FX system are involved in the acetate metabolic responses to the 1st exposure of immobilization stress, and secondly, that only the AMYG-ST is involved in the disappearance process of acetate metabolic responses to immobilization stress by the daily repetition of immobilization stress.

Influence of lesions in the limbic-hypothalamic system on metabolic response of acetate to daily repeated heat exposure in rabbit.

The effects of lesions in the basal medial hypothalamus and limbic structure on the acetate metabolic responses to daily repeated heat exposure in the liver of rabbits have been investigated. The results obtained were summarized as follows: (1) THe acetate metabolic responses to the 1st heat exposure (heat exposure on the 1st day) were altered by the lesions in the periventricular arcuate nucleus (ARC), ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). (2) The acetate metabolic responses to heat exposure were completely abolished by the ten times repetition of heat exposure in the rabbits with lesions in ARC or VMH. They were similar to sham-operated animals. (3) The acetate metabolic responses to heat exposure remained even after the ten times repetition of heat exposure in the rabbits with lesions in ST and FX indicating the differences from sham-operated animals. (4) From these results, it might be suggested that the basal medial hypothalamus and limbic structure participated in the mechanism of acetate metabolic response to the 1st heat exposure, but only these limbic structure played some roles in the complete disappearance process of acetate metabolic responses to heat exposure by the ten times repetition of heat exposure.

Influence of lesion of the limbic-hypothalamic system on metabolic responses of acetate to daily repeated cold exposures in rabbits.

The effects of the lesions of basal medial hypothalamus and limbic structure on the acetate metabolic responses to daily repeated cold exposures in rabbit's liver has been investigated. The results obtained were summarized as follows: (1) The lesions of periventricular arcuate nucleus (ARC) had no effects on the acetate metabolism and on the acetate metabolic responses to the 1st cold exposure (cold exposure on the 1st day). (2) The metabolic pattern of acetate and the acetate metabolic responses to the 1st cold exposure were altered by the lesions of ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). (3) The effects of cold exposure on the acetate metabolism were completely abolished by the seven times repetition of cold exposures in the rabbits with the lesions of ARC, VMH or ST, as the same as in each sham-operated group. (4) The acetate metabolic responses to cold exposure remained after the seven times repetition of cold exposure in the rabbits with the lesions of FX, but those disappeared completely in sham-operated animals. (5) From these results, it might be suggested that the VMH, amygdala(AMYG)-ST system, dorsal hippocampus(HPC)-FX system played some roles in the metabolic regulation of acetate and in the mechanisms of acetate metabolic responses to the 1st cold exposure, but the ARC did not participate in those mechanisms. And it was suggested that the HPC-FX system participated in the acetate metabolic adaptation to daily cold exposures, but the basal medial hypothalamus and AMYG-ST system did not participate in this process.

Influence of lesions of the limbic-hypothalamic system on adrenocortical responses to daily repeated heat exposures in rabbits.

The effects of lesions in the basal medial hypothalamus and limbic structure upon the responses of adrenocorticoids formation in adrenal slices of rabbits to daily repeated heat exposures has been investigated. (1) The adrenocortical responses to heat exposure on the 1st day were decreased by lesions in the periventricular arcuate nucleus (ARC), ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). (2) There were no effects of heat exposure on the 10th day upon the adrenocorticoid formation in either the sham-lesioned rabbits or the rabbits with the lesions of ARC, VMH and ST. (3) In rabbits with the FX lesions, the adrenocorticoids formation was significantly increased by heat exposure on the 10th day. (4) These results suggested that the basal medial hypothalamus, amygdala (AMYG)-ST system and dorsal hippocampus (HPC)-FX system participated in the mechanisms of adrenocortical responses to heat exposure on the 1st day, but only the HPC-FX system played some roles in complete disappearance process of adrenocortical responses to heat exposure by repetition of exposures.

Influence of lesions in the limbic-hypothalamic system on adrenocortical responses to daily repeated exposures to immobilization stress in rabbits.

In order to elucidate the role of the limbic-hypothalamic system in the adrenocortical responses to repeated immobilization stress, the influences of daily repeated exposures of immobilization stress on the adrenocorticoid formation in adrenal slices of rabbits with lesions of various sites of the hypothalamus and limbic structures had been investigated. The experimental results obtained were as follows: (1) Lesions in periventricular arcuate nucleus (ARC) and ventromedial hypothalamus (VMH) decreased the rates of adrenocortical responses to the 1st immobilization exposure (exposure on the 1st day), but did not alter the rates of adrenocortical responses to the 4th immobilization exposure (exposure on the 4th day). (2) Lesions in stria-terminalis (ST) and dorsal fornix (FX) did not alter the rates of adrenocortical responses to the 1st immobilization exposure, but increased the rates of adrenocortical responses to the 4th immobilization exposure. (3) The adrenocortical responses to immobilization stress were completely abolished by the seven times repetition of exposures in each sham-operated group and in the animals with lesions of ARC and VMH, but in the rabbits with lesions of ST and FX the adrenocortical responses to immobilization stress were not abolished by the seven times repetition of exposures. (4) These results suggested that such basal medial hypothalamus participated in the mechanisms of adrenocortical responses to the 1st exposure of immobilization stress, but did not participate in the disappearance process of adrenocortical responses to immobilization stress by the seven times repetition of exposures. On the other hand, it might be supposed that the amygdala(AMYG)-ST system and dorsal hippocampus(HPC)-FX system do not participate in the mechanism of adrenocortical responses to the 1st immobilization exposure, but these limbic areas played some roles in the disappearance process of the adrenocortical responses to immobilization stress by the seven times repetition of exposures.

Influence of repeated cold exposures on adrenocorticoid formation in rabbits with lesioned limbic-hypothalamic system.

Experiments were carried out in the rabbit, with view to elucidating the role of limbic-hypothalamic system in the adrenocortical responses to repeated cold exposures. In each sham-lesioned group, in the rabbit with lesioned in bilateral stria terminalis and dorsal fornix, the formation of adrenocorticoids in adrenal was markedly increased by 1st cold exposure (cold exposure on 1st day), with the adrenocortical responses to 1st cold exposure being nearly the same in these groups. The bilateral lesions in periventricular arcuate nucleus and ventromedial hypothalamus decreased the adrenocortical responses to 1st cold exposure. In each sham-lesioned group, and in the rabbits with lesioned in bilateral periventricular arcuate nucleus, ventromedial hypothalamus and dorsal fornix, there were no effects of 7th cold exposure (cold exposure on 7th day) on the formation of adrenocorticoids. However, in the rabbits with lesioned in bilateral stria terminalis, the formation of adrenocorticoids was markedly increased by the 7th cold exposure. From these results it might be suggested that periventricular arcuate nucleus and ventromedial hypothalamus participated to adrenocortical response to 1st cold exposure, and the amygdala-stria terminalis system played some role in the establishment of adaptation to repeated cold exposures in adrenocortical responses.

Antidromic identification of neurons in the ventrolateral part of the medulla oblongata with ascending projections to the preoptic and anterior hypothalamic area (POA/AHA).

Seventy neurons in the ventrolateral medulla oblongata were antidromically activated by electrical stimulation of the preoptic and anterior hypothalamic area (POA/AHA) in female rats under urethane anesthesia. These identified cells were located within and adjacent to the nucleus reticularis lateralis and could be readily distinguished into at least two types of neurons, designated as "fast' and "slow' cells, on the basis of their waveform and conduction velocity.