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Biomedical subjects

X R Yuan

Publications and source records attributed to X R Yuan.

10 recordsLinked to original sources
PubMed2000

[Experimental study on effect of sanmiao mixture capsules on prostate hyperplasia in mice and rats].

OBJECTIVE: To observe the effect of Sanmiao Mixture Capsules(SMC) on prostate hyperplasia in mice and rats. METHOD: The model of prostate hyperplasia was made by injecting testosterone propionate in to male mice(5 g.kg-1.d-1, 21 d) and rats(3 g.kg-1.d-1, 14 d). The treated group was administered SMC(mice: 36.3 g.kg-1 and 18.2 g.kg-1; rats: 25.2 g.kg-1 and 12.6 g.kg-1), the normal control group 1.9 g.kg-1, and the model control group NS. hours after the last administration serum tests were carried out on E2, AKP and Zn2+. Then the animals were killed, prostates taken out and weighed, index of prostate was calculated and pathological examination performed. RESULT: In the SMC treated group, the prostate weight and index were lowered(P < 0.01) the mean activation of E2 was raised, and the mean concentration of AKP and Zn2+ was inhibited (P < 0.01). CONCLUSION: SMC are helpful in checking prostate hyperplasia in mice and rats, the mechanism being probably related to the raising of activation of E2 as well as to the inhibition of concentration of AKP and Zn2+.

Acid Phosphatase↗
PubMed1996

[Inhibitory effects of three opioid receptor agonists on synaptic transmission].

AIM: To compare the inhibitory effects of 3 opioid receptor agonists, (D-Ala2, NMe-Phe4, Gly-ol)-enkephalin (DAGO), (D-Pen2,5)-enkephalin (D-PEN), and trans-(+/-)-3, 4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl) cyclohexyl]-benzeneacetamide methanesulfonate (U-50488H) in different concentrations on synaptic transmission. METHODS: The excitatory postsynaptic potentials (EPSP) in slice preparation of nucleus accumbens of rats were recorded using electric stimulation of the olfactory tubercle area and intracellular micropipettes filled with potassium acetate (3 mol.L-1). RESULTS: Superfusion of DAGO, D-PEN, and U-50488H (1 mumol.L-1) reduced the amplitude of EPSP and the inhibitory effect on EPSP were reversed by superfusing naloxone (Nal, 1 mumol.L-1), in which the DAGO-induced reduction of synaptic transmission was the most effective. The depolarizing responses to microiontophoretic injection of glutamate were reduced by superfusing DAGO in 19 neurons of slice preparation of nucleus accumbens. CONCLUSION: The inhibitory effects of DAGO, D-PEN, and U-50488H on EPSP were in a concentration-dependent manner, and the mechanism of opioid agonists (at least DAGO) reducing EPSP was related to a decrease of postsynaptic transmission mediated by glutamate.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1993

[The effects of opioid peptides on postsynaptic potentials in slice preparation of nucleus accumbens of rats].

Behavioral studies indicate that nucleus accumbens (NAcc) is a key brain area for the rewarding effects of opiate and for opiate addiction. To find out the cellular correlates of opiate addiction, the effects of three kinds of opiate peptides on membrane potential and postsynaptic potentials (PSPs) in a slice preparation of NAcc were studies by intracellular recording and current-clamp technique. The results indicated that superfusion of opioid 7 peptides did not affect membrane potential and input resistance of NAcc neurons, but significantly reduced postsynaptic potentials. Naloxone superfusion significantly reversed the depressant effects of mu and sigma receptor agonist (DAGO, D-Pen) on PSPs, but not on those of kappa agonist (U-50). These results suggest that opioid peptides predominantly reduce synaptic transmission in NAcc.

Animals↗
PubMed1993

[Role of nucleus accumbens in cardiovascular activities and its relationship with opioid peptides in rats].

In this study, electrical stimulation and microinjection in nucleus accumbens in urethane-anesthetized rats were conducted to observe the effect of electrical stimulation of nucleus accumbens on blood pressure and heart rate. The following results were observed: (1) Electrical stimulation of the nucleus accumbens of rat resulted in significant hypotension and bradycardia. (2) Kainic acid microinjected into the nucleus accumbens, could abolish the effects mentioned above. (3) Naloxone administered to the nucleus accumbens could block the cardiovascular inhibitory effect evoked by electrical stimulation of nucleus accumbens. The intra-accumbens injection of mu-receptor agonist, DAGO could also elicit hypotension and bradycardia to an extent comparable to that of the effect due to electrical stimulation, whereas kappa-receptor agonist, U-50 had no such an effect. (4) When the cardiovascular inhibitory effect elicited by electrical stimulation of the nucleus accumbens was observed, the discharge activity in locus ceruleus was also decreased. (5) Bilateral vagotomy could abolish the change in heart rate elicited by the electrical stimulation of nucleus accumbens, but not the hypotension. It is suggested that the mu-opioid receptors of neurons in nucleus accumbens are involved in cardiovascular activity.

Animals↗
PubMed1992

Opioid peptides reduce synaptic transmission in the nucleus accumbens.

Behavioral studies implicate the nucleus accumbens (NAcc) as a brain area pivotal for the rewarding effects of opiates like heroine and morphine. Therefore, we studied the effect of a variety of opioids on membrane properties and responses to synaptic stimulation in a slice preparation of the NAcc using intracellular recording. Superfusion of opioid peptides did not affect the membrane potential or input resistance of NAcc neurons, but significantly reduced both depolarizing and hyperpolarizing synaptic potentials. Naloxone superfusion significantly reversed the depressant effects of the mu and delta receptor agonists (but not those of the kappa agonist) on synaptic transmission, suggesting involvement of opiate receptors. These results imply that the predominant effect of opiates in NAcc is a reduction of synaptic transmission.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗