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Biomedical subjects

Y Ukai

Publications and source records attributed to Y Ukai.

78 records · Page 5Linked to original sources
PubMed1980

Effects of tyrosyl-arginine (kyotorphin), a new opioid dipeptide, on single neurons in the spinal dorsal horn of rabbits and the nucleus reticularis paragigantocellularis of rats.

The effects of a new endogenous opioid dipeptide (Tyr-Arg), kyotorphin, on single unit activities recorded from the lamina V type neurons in the spinal dorsal horn and the neurons in nucleus reticularis paragigantocellularis (NRPG) of the medulla oblongata were investigated in the rabbit and rat, respectively. Microelectrophoretically applied kyotorphin predominantly depressed the lamina V type neurons but excited the NRPG neurons. Such predominant effects were antagonized by naloxone. These results suggest that kyotorphin has qualitatively similar actions to those of enkephalins in both central regions examined.

Animals↗
PubMedDate not supplied

Behavioral and electroencephalographic studies of beagles with an Eck's fistula: suitability as a model of hepatic encephalopathy.

Behavioral manifestations, electroencephalograms (EEGs) and visually evoked potentials (VEPs) were studied in beagles with Eck's fistula (portacaval shunt [PCS]), an established model of hyperammonemia, to determine whether they developed CNS disorders characteristic of hepatic encephalopathy. After PCS, behavioral changes occurred in the form of listlessness, sluggishness (altered gait, snapping and transient catatonia-like symptoms) and apparent blindness, which appeared in that order and progressed to coma and death in some animals. The EEGs from the frontal cortex showed a gradual decrease in voltage and frequency. Development of snapping and catatonia-like symptoms coincided with the occurrence of high voltage fast waves in the EEGs from the occipital cortex. In comatose Eck's fistula dogs. flattening of the EEGs was recorded from the frontal cortex and a lowered voltage was noted in the EEGs from the occipital cortex. After PCS, the latencies and amplitudes of the components of VEP were increased. The snapping and catatonia-like symptoms were markedly ameliorated by carbamazepine and the coma by flumazenil and thyrotropin-releasing hormone. These findings indicate that Eck's fistula dogs provide a useful model of hepatic encephalopathy.

Ammonia↗
PubMedDate not supplied

Muscarinic supersensitivity and subsensitivity induced by chronic treatment with atropine and diisopropylfluorophosphate in rat submaxillary glands.

Rats were given atropine for 2 weeks and a cholinesterase inhibitor, diisopropylfluorophosphate (DFP) for 4 weeks. The secretory response of the submaxillary glands to pilocarpine and the muscarinic receptor binding to [3H]quinuclidinyl benzylate (QNB) and [3H]pirenzepine (PZ) in the submaxillary glands were investigated. Experiments were performed 48 and 24 hr after the last administration of atropine and DFP, respectively. Chronic atropine treatment enhanced the secretory response and increased the number of binding sites for [3H]QNB and [3H]PZ. The increase in number of binding sites for the 2 radioligands was almost the same. Chronic DFP treatment caused a marked decrease in the secretory response to pilocarpine, without affecting [3H]PZ and [3H]QNB binding. These results suggest that the cholinergic muscarinic M1 receptors may contribute to the development of the supersensitivity of the salivary glands caused by atropine, but not to the development of subsensitivity caused by DFP.

Animals↗
PubMedDate not supplied

Enhancement of salivary secretion by chronic anethole trithione treatment.

Effect on salivary secretion of a single dose and of chronic treatment with trithio-p-methoxyphenylpropene (anethole trithione; ANTT) was investigated in mice, rats and rabbits in relation to changes in function of the autonomic nervous system. Chronic treatment with ANTT enhanced salivary secretion induced by pilocarpine or electrical stimulation of the parasympathetic nerve, but had no effect on salivary secretion induced by isoproterenol or phenylephrine. A single dose of ANTT had no effect on salivary secretion. Chronic treatment with ANTT prevented the inhibition of parotid salivary secretion caused by atropine in rabbits. Choline acetyltransferase and acetylcholinesterase activities in rat submaxillary glands were not affected by chronic treatment with ANTT. These results suggest that chronic treatment with ANTT may enhance salivary secretion by stimulating the postjunctional secretory process involved in the parasympathetic nervous system.

Anethole Trithione↗