[Studies on histamine containing cells in the spleen of the magnesium-deficient rats].

When young Wistar rats (body wt. 50 g) were maintained on a magnesium-deficient diet (0.001% Mg) for eight days, the splenic weight and histamine content increased about 2-fold and 30-fold, respectively, compared with those of the control rats.

[Effects of magnesium deficiency on dermal mast cells in rats].

The effects of dietary magnesium (Mg) deficiency on dermal mast cells were studied in young Wistar rats weighing about 50 g. The rats fed with a Mg-deficient diet (0.001% Mg) showed hyperemia on the 3rd or the 4th day after they were fed the diet.

Role of adrenergic alpha-receptors in regulation of acetylcholine release evoked by distension of guinea pig ileum.

The significance of adrenergic nerves in the regulation of acetylcholine (ACh) release evoked by distension of the guinea pig ileum was evaluated by pharmacological manipulations. ACh release was measured by bioassay. Release in response to distension was completely abolished by epinephrine and norepinephrine.

Effects of adenylate cyclase inhibitors, phosphodiesterase inhibitors, and dibutyryl cyclic AMP on spontaneous and various stimuli-induced acetylcholine release from guinea pig ileum myenteric plexus.

In order to examine a possible contribution of cyclic AMP to acetylcholine (ACh) release from guinea pig ileum myenteric plexus, effects of adenylate cyclase inhibitors, phosphodiesterase (PDE) inhibitors and dibutyryl cyclic AMP on the spontaneous and the various stimuli-induced ACh release were investigated. A PDE inhibitor, theophylline (1 mM) increased the ACh release induced by nicotine (6.16 microM) significantly.

Effects of bifemelane hydrochloride (MCI-2016) on acetylcholine level reduced by scopolamine, hypoxia and ischemia in the rats and mongolian gerbils.

Effects of bifemelane hydrochloride (MCI-2016) on acetylcholine (ACh) level in the cerebral cortex and hippocampus of rats and Mongolian gerbils were examined. In normal rats, MCI-2016 (30 mg/kg, i.p.

Involvement of the cholinergic mechanism in DDT and dieldrin action in the insect central nervous system.

The effects of DDT and dieldrin on cholinergic neurotransmission were studied using the sixth abdominal ganglion of the cockroach. Spontaneous electrical discharges in the ganglion recorded with an extracellular electrode were augmented by 0.1 mM DDT and 1 microM dieldrin.

The role of sialic acid in the nerve terminal for the release of transmitter.

The role of sialic acid in the frequency of miniature endplate potentials (MEPPs) was examined using neuraminidase and gangliosides in the mouse diaphragm. Neuraminidase increased and decreased MEPP frequency in normal K+ and high K+ solution, respectively. The effects were dependent on the presence of Ca2+ in extracellular medium.

Transmitter release at the mouse neuromuscular junction stimulated by cadmium ions.

Cadmium ion (Cd2+) was examined for effects on frequency of miniature end-plate potentials (m.e.p.

Contribution of endogenous prostaglandins to excitation of the myenteric plexus of guinea-pig ileum: are adrenergic factors involved?

The role of endogenous prostaglandins (PGs) in the nicotine-induced contraction and release of ACh was investigated in the isolated guinea-pig ileum. A low concentration of indomethacin (IND 2.8 microM) inhibited the contraction and ACh release induced by nicotine.

Involvement of adrenergic and serotonergic nervous mechanisms in allethrin-induced tremors in mice.

Oral or intravenous administration of allethrin, a synthetic derivative of the pirethrin-based insecticides, produces neurotoxic symptoms consisting of mild salivation, hyperexcitability, tremors and convulsions which result in death. Intracerebroventricular injection of allethrin to mouse at about one-nineth the dose of intravenous administration, produced qualitatively identical but less prominent symptoms, indicating that at least some of the symptoms may be originated in the central nervous system. To investigate the mechanism of action of the compound, we studied the ability of agents which alter neurotransmission to prevent or potentiate the effect of convulsive doses of technical grade (15.

Involvement of cholinergic mechanism in the action of allethrin in insect CNS.

Allethrin had a stimulating action on spontaneous discharges in the cockroach sixth abdominal ganglion superfused with an insect saline solution. This action at a low concentration (5 X 10(-8) M) of allethrin was abolished by either of d-tubocurarine, hexamethonium or atropine at 5 X 10(-4) M. It was also abolished by the treatment of ganglia with hemicholinium-3 or by low-calcium-high magnesium insect saline solution.

Neuropharmacological effect of methylmercury in mice with special reference to the central cholinergic system.

Effect of methylmercury chloride (MMC) on behavior was studied in male ICR-JCL mice. In order to clarify the causal relationship between the potent suppressing action of MMC on the central cholinergic system and toxic manifestations, behavioral changes induced by MMC were compared with those induced by the two reference drugs, hemicholinium-3 (HC-3) and 3'-chloro-4-stilbazole (CS; a potent choline acetyltransferase inhibitor). When administered intraperitoneally, daily in a dose of 5 mg Hg/kg/day, MMC caused a decrease in spontaneous motor activity, rotarod dysfunction, and hypothermia before an abrupt loss in body weight and the appearance of overt signs.

Acetylcholine release from the myenteric plexus of guinea-pig ileum by prostaglandin E1.

Release of acetylcholine (ACh) by prostaglandin E1 from the nerve terminals of the guinea-pig longitudinal muscle strip was studied in order to reveal the effect of PGE1 on myenteric plexus activity. The ACh released was collected in the presence of physostigmine (2.1 microgram ml-1) and choline (0.

Release of prostaglandins from the passively distended wall of guinea pig small intestine.

The effects of the radial distension of the intestinal wall and the increased intraluminal pressure on the liberation of prostaglandins (PGs) were studied with the isolated guinea pig ileum. Both procedures were accompanied by an increased output of a prostaglandin-like substance and the release was proportional to the degree of distension or intraluminal pressure. Thin-layer chromatography coupled with bioassay suggested that this substance may be a mixture of PGF2 alpha, PGE2 and PGE1.

[Oral propagation of the circular muscle contraction induced by local distension of the isolated guinea pig ileum (author's transl)].

The local distension of the intestinal wall was carried out by inflating a thin rubber balloon which had been fixed in the lumen and the contractions of the circular muscle were recorded at the points of 5 mm (PO1) and 20 mm (PO2) oral to the fixed balloon. The contractions elicited by local distension was blocked by tetrodotoxin and atropine, or removing longitudinal muscle, with the myenteric plexus adhering to it, from the intestine at the distending region. When 2 to 3 mm length of longitudinal muscle was stripped off around the intestine between PO1 and PO2, the contraction initiated at PO1 never reached to PO2.

Effects of methylmercury chloride on various cholinergic parameters in vitro.

The effects of methylmercury chloride and other mercury compounds on cholinergic parameters were studied in vitro. Methylmercury chloride (MMC) and phenylmercury acetate inhibited choline acetyltransferase (ChA) with 20 microM of I50, and mercury nitrate (MN) with 100 microM of I50. All the three compounds had little effect on cholinesterase activity.

Descending release of acetylcholine from the locally distended guinea pig ileum.

The effects of local distension of the intestinal wall on the release of acetylcholine (ACh) from the adjacent non-distended part were studied with the segment os isolated guinea pig ileum. Local distension of the intestinal wall induced the increased release of ACh in the distended part and in its anal side but not in its oral side. Such aboral release of ACh by local distension was abolished by tetrodotoxin or atropine in the concentrations which did not block the release in the distended part.

Changes of tissue acetylcholine in the distended intestine.

The effects of distension of the intestinal wall on the liberation and the synthesis of acetylcholine (ACh) were studied in the isolated guinea-pig ileum measuring the changes in the amount of free and bound ACh. In the presence of eserine longitudinal distension increased the amount of bound ACh in the intestinal wall without increasing the free ACh, while circumferential distension or mucosal rubbing increased free but not bound ACh. These effects were evident within 30 sec.