Relationship between genetic polymorphism of MCP-1 and non-small-cell lung cancer in the Han nationality of North China

Monocyte chemoattractant protein 1 (MCP-1) is an important chemokine that has a dose-dependent anti-tumoral effect. Polymorphism in the MCP-1 distal regulatory region (-2518A/G) can affect the level of MCP-1 expression. We examined the polymorphisms of 112 unrelated patients with non-small-cell lung cancer (NSCLC) and 82 unrelated healthy controls of Han nationality in North China using PCR-RFLP. We found that the distributions of AA, AG and GG genotypes of MCP-1-2518 were significantly different in NSCLC patients compared to controls (chi(2) = 10.106, P = 0.006). There was a significant increase in the frequency of the AA genotype (odds ratio (OR) = 3.138, chi(2) = 8.905, P = 0.003) and a significant decrease in the frequency of the GG genotype (OR = 0.516, chi(2) = 4.613, P = 0.032) in the NSCLC patients, compared to controls. The frequencies of AA, AG and GG genotypes did not differ in the NSCLC patients according to the number of pack-years smoked. Based on these results, we suggest that the MCP-1 -2518A/G polymorphism is associated with genetic susceptibility to NSCLC.

Analysis of HLA-A, HLA-B and HLA-DRB1 alleles in Chinese patients with lung cancer

The primary function of the human leukocyte antigen (HLA) system is to regulate the immune response. Because of its important role in the immune response and its high degree of polymorphism, the HLA system is associated with many diseases. We examined the polymorphisms of HLA-A, B and DRB1 alleles in 100 unrelated patients with lung carcinoma and in 438 unrelated normal controls of Han nationality from North China, using sequence-based typing and PCR with sequence-specific primers. We found that the frequencies of HLA-A*0201, A*2601, B*1518, B*3802, DRB1*0401, DRB1*0402, and DRB1*1201 were higher in the lung carcinoma group than in the normal control group. The P values were 0.035, 0.040, 0.001, 0.017, 0.014, 0.004, and 0.019, respectively, and the odds ratio values were 1.052, 3.513, 4.047, 3.054, 4.237, 19.397, and 2.128, respectively. The frequency of HLA-DRB1*1302 was lower in the lung carcinoma group than in the normal control group (P = 0.046, odds ratio = 0.168). We concluded that patients with lung cancer and healthy controls of Han nationality from North China differ in the frequencies of various HLA alleles.

Intrinsic anisotropy of degree of transport spin polarization in typical ferromagnets

A general approach is presented for investigation of the anisotropy of the degree of transport spin polarization (P) in ferromagnets both in the ballistic regime, P(1,i), and in the diffusive regime, P(2,i), as a function of crystal direction. The validity of this approach is confirmed by the benchmark calculation for the isotropic P. By this approach, we have investigated the anisotropy of P in bcc Fe, fcc Co, fcc Ni and hcp Co. For cubic structures, P(1,i) shows a small but appreciable anisotropy, due to the difference in the electronic orbital extension for spin-up and spin-down conduction bands. However, P(2,i) shows an isotropic feature for the cubic structure, as a result of the combination of its dependence on the square of electron velocity and the lattice symmetry. On the other hand, for hcp Co, both P(1,i) and P(2,i) show a very strong anisotropy. The large anisotropy of P(1,i) and P(2,i) in hcp Co is mainly attributed to the anisotropy of spin-down ballistic (diffusive) conductance.

[Effect of melatonin on release of beta-endorphin, norepinephrine and 5-hydroxytryptamine in rat brain]

AIM

In order to explore the mechanism of action of melatonin to induce analgesia, the present study was undertaken to observe the effects of melatonin on the release of beta-endorphin (beta-Ep), norepinephrine (NE) and 5-hydroxytryptamine in rat brain.

METHODS

With the measurement of pain threshold, push-pull perfusion technique and radioimmunoassay were used to determine the immunoreactive beta-Ep content in the perfusate from the third ventricle of rat brain. The contents of 3-methoxy-4-hydroxyphenyl glycol (MHPG) and 5-hydroxyindole acetic acid in the microdialysate from rat brain were measured by techniques of in vivo microdialysis and high performance liquid chromatography with electrochemical detection.

RESULTS

The immunoreactive beta-Ep content in the perfusate from the third ventricle of rat brain was increased significantly (P < 0.05) following an intraperitoneal administration of 110 mg.kg-1 of melatonin, with the increase of pain threshold. The MHPG and 5-HIAA contents in the microdialysate from the periaqueductal gray (PAG) or the hypothalamus were not changed after the administration of melatonin.

CONCLUSION

Melatonin may promote the release of beta-Ep in brain, which may be one of the mechanisms of the analgesic action of melatonin. The analgesic action of melatonin may not be related to the release of NE and 5-HT in the PAG or the hypothalamus.

The analgesic effects of peripheral and central administration of melatonin in rats

To explore the site and mechanism of the analgesic action of melatonin, the present study was designed to evaluate the analgesic effects of intraperitoneal (i.p.) and intracerebroventricular (i.c.v. ) administration of melatonin, and to investigate the effect of i.c. v. naloxone on the analgesic effect induced by i.p. melatonin in rats. Antinociception was determined by tail-flick latency to hot water at 50 degrees C. On i.p. administration, melatonin (30, 60 and 120 mg/kg) produced the antinociceptive effect in a dose-dependent manner, with an A(50) of 72.8 mg/kg. Administered i.c.v., melatonin (0.25, 0.5 and 1 mg/kg) also resulted in dose-dependent antinociception, with an A(50) of only 0.693 mg/kg. Injected i.c.v. to rats, 10 microg of naloxone antagonized significantly the antinociceptive effect induced by i.p. melatonin. It is concluded that melatonin has an analgesic effect in rats and the central nervous system (CNS) may be the primary site for melatonin to elicit the response, and the effect of melatonin is related to the central opioid system.

Polychlorinated organic compounds (PCOCs) in waters, suspended solids and sediments of the Yangtse River

The contamination levels of polychlorinated organic compounds (PCOCs) in waters, suspended solids and sediments of the Yangtse River (Nanjing part) were analyzed in this paper. Their concentrations determined by GC/MS were very low in comparison with those in European River. The average concentration of total HCH (alpha-HCH, beta-HCH, gamma-HCH) was much higher than that of other PCOCs in all waters, which made up 65% of total amount of PCOCs. Due to the complete dilution and mixture of pollutants in the mighty Yangtse River, the content of PCOCs at each sampling station demonstrated very similar spatial pattern for waters and suspended solids. Since the small suspended solid (<0.7 microm) passed through the filter was also considered as dissolved part, the dominant parts of HCHs, PCA and PCBs were found in dissolved phase with percentage proportion of 85-94%, 72-85% and 61-78%, respectively. For DDTs, HCB and PeCB, their contents in dissolved phase were slightly higher than in particulate phase. The contents of PCOCs in sediments were also very low and varied with high fluctuation at different sampling points, indicating the heterogeneous deposition. HCB and its metabolite (PeCB) presented the highest contamination levels among PCOCs in sediments.

[Melatonin influences the release of endogenous opioid peptides in rat periaqueductal gray]

The present study was undertaken to explore central mechanisms underlying the analgesic effect of melatonin. Push-pull perfusion technique and radioimmunoassay were used to observe the changes in the contents of beta-endorphin (beta-Ep) and leucine-enkephalin (L-EK) in the perfusate from the rat periaqueductal gray (PAG) after administration of melatonin. 30 50 min after an intraperitoneal injection of melatonin (110 mg/kg), the beta-Ep content in the perfusate was increased significantly, while the L-EK content was not changed. Pain threshold was measured using the warm water tail-flick test during the push-pull perfusion of the PAG. It was found that the rat pain threshold was increased significantly 40 min after the intraperitoneal injection of melatonin (110 mg/kg). The results suggest that melatonin may promote the release of beta-Ep in the PAG, which may be one of the mechanisms of the analgesic effect of melatonin.

Melatonin attenuates the intensity of beta-endorphin immunoreactivity in the arcuate nucleus of rat hypothalamus

The present study was undertaken to observe the effect of exogenously administered melatonin on the intensity of beta-endorphin (beta-Ep) immunoreactivity of the neuron in the arcuate nucleus of rat hypothalamus with an aim to explore the possible mechanisms of the analgesic effect of melatonin. The experimental rats were divided into two groups, one injected intraperitoneally with melatonin (110 mg/kg) and the other with only a vehicle. One hour after injection, the brain was processed for coronal sections, which were stained with immunohistochemical ABC technique. The integral optical density (IOD) and mean optical density (OD) of the stained sections were measured with a computer-assisted image-processing and analytical system. beta-Ep immunoreactivity was much decreased in the sections treated with melatonin and the IOD and OD were also decreased significantly (P<0.01; P<0.05). The above results suggest that melatonin may result in a decrease of beta-Ep content in the arcuate nucleus, as a result of increased beta-Ep release induced by administration of melatonin. It is likely that the analgesic effect of melatonin may be in part mediated by the release of beta-endorphin from the arcuate nucleus.

Effect of melatonin on pro-opiomelanocortin mRNA expression in arcuate nucleus of rat hypothalamus

AIM

To observe altered expression of pro-opiomelanocortin (POMC) mRNA localized in neurons in the arcuate nucleus of rat hypothalamus following exogenous administration of melatonin.

METHODS

The experimental animals were divided into two groups injected i.p. with melatonin 90 mg.kg-1 and vehicle at 12 h interval (9:00 am and 9:00 pm). Twelve hours after the last injection, the rat brains were processed for coronal sections and nonradioactive in situ hybridization histochemistry technic was used. The integral optical density (IOD) and mean optical density (OD) of the stained brain sections were measured using the computer-assisted image processing technique.

RESULTS

The POMC mRNA expression in the arcuate nucleus showed obvious enhancement in the brain sections of rats treated with melatonin. The IOD and OD values in the hypothalamic arcuate nucleus area were increased significantly (P < 0.01, P < 0.05 respectively) with melatonin treatment.

CONCLUSION

Melatonin may enhance the POMC mRNA expression in the arcuate nucleus of rat hypothalamus.

Selective MT(2) melatonin receptor antagonist blocks melatonin-induced antinociception in rats

The present study was undertaken to assess the effects of intracerebroventricular (i.c.v.) luzindole (a selective MT(2) melatonin receptor antagonist) and prazosin (a selective MT(3) melatonin receptor antagonist) on melatonin-induced antinociception, so as to clarify which of melatonin receptor subtypes within the central nervous system (CNS) was mediating antinociception. The pain threshold of rats was measured by the hot water (50 degrees C) tail-flick test. It was found that intraperitoneal (i.p.) melatonin (30, 60, 120 mg/kg) resulted in a dose-dependent antinociception. Luzindole (50, 100 microgram) administered intracerebroventricularly antagonized significantly the antinociceptive effect induced by i.p. melatonin (120 mg/kg), whereas prazosin (50 microgram) did not. Neither luzindole (100 microgram, i.c.v.) nor prazosin (50 microgram, i.c.v.) affected the nociceptive threshold when given alone. The results suggest that melatonin-induced antinociception is mediated through the MT(2) melatonin receptor subtype within the CNS.

Effects of fenfluramine combined with electroacupuncture on monoamine release in periaqueductal gray of rat brain

AIM

To study the changes of monoamines in ventrolatoral periaqueductal gray of rat brain before and after electroacupuncture (EA) analgesia (EAA) was enhanced by fenfluramine (Fen), a 5-hydroxytryptamine (5-HT) releaser.

METHODS

Monoamines were collected by in vivo microdialysis and measured by HPLC connected with electrochemical detector.

RESULTS

The level of norepinephrine (Nor) after EA was decreased (P < 0.05 vs NS group). The contents of 5-HT, 5-hydroxyindol acetic acid (5-HIAA), dopamine (DA), and homovanillic acid (HVA) in periaqueductal gray dialysate were increased (P < 0.05 vs NS group). When Fen was combined with EA, the level of 5-HT and 5-HIAA were further increased (P < 0.05 vs NS + EA group). There was no obvious change of Nor, DA, and HVA.

CONCLUSION

Fen potentiating EAA may be related to further activation of serotoninergic system.

Distinct leukemia phenotypes in transgenic mice and different corepressor interactions generated by promyelocytic leukemia variant fusion genes PLZF-RARalpha and NPM-RARalpha

Acute promyelocytic leukemia (APL) is characterized by a specific chromosome translocation involving RARalpha and one of four fusion partners: PML, PLZF, NPM, and NuMA genes. To study the leukemogenic potential of the fusion genes in vivo, we generated transgenic mice with PLZF-RARalpha and NPM-RARalpha. PLZF-RARalpha transgenic animals developed chronic myeloid leukemia-like phenotypes at an early stage of life (within 3 months in five of six mice), whereas three NPM-RARalpha transgenic mice showed a spectrum of phenotypes from typical APL to chronic myeloid leukemia relatively late in life (from 12 to 15 months). In contrast to bone marrow cells from PLZF-RARalpha transgenic mice, those from NPM-RARalpha transgenic mice could be induced to differentiate by all-trans-retinoic acid (ATRA). We also studied RARE binding properties and interactions between nuclear corepressor SMRT and various fusion proteins in response to ATRA. Dissociation of SMRT from different receptors was observed at ATRA concentrations of 0.01 microM, 0.1 microM, and 1.0 microM for RARalpha-RXRalpha, NPM-RARalpha, and PML-RARalpha, respectively, but not observed for PLZF-RARalpha even in the presence of 10 microM ATRA. We also determined the expression of the tissue factor gene in transgenic mice, which was detected only in bone marrow cells of mice expressing the fusion genes. These data clearly establish the leukemogenic role of PLZF-RARalpha and NPM-RARalpha and the importance of fusion receptor/corepressor interactions in the pathogenesis as well as in determining different clinical phenotypes of APL.

[Effect of intrathecal injection of dopamine receptor agonists/antagonists on pain and acupuncture analgesia in rats]

Some selective dopamine receptor agonists and antagonists were tested on rat tail flick model to investigate the role of D1 and D2 dopamine receptor in pain and acupuncture analgesia (AA). It was found that intrathecal administration (i.t.) of D2 receptor agonist LY171555 or D1/D2 receptor agonist apomorphine increased pain threshold and had a potentiating effect on AA. In contrast, D1 receptor agonist SKF38393 had no effect. It D1 receptor antagonist SCH23390 or D2 receptor antagonist sulpiride attenuated the effect of AA. The results suggest that D2 receptor is involved in pain modulation and activation of D2 receptor and enhances AA in the spinal cord, while such effect is absent in D1 receptor and inactivation of D1 receptor attenuates AA.

Antagonistic effect of orphanin FQ on opioid analgesia in rat

AIM

To study the effect of orphanin FQ (OFQ), a newly discovered heptadecapeptide, on nociception and opioid analgesia.

METHODS

The intracerebroventricular (i.c.v.) and intrathecal (i.t.h.) injections were used to give the drugs. The tail-flick model of rats were used to test the pain threshold.

RESULTS

OFQ (i.c.v. or i.t.h.) 0.1 microgram had no effect on nociception but 0.5-10 micrograms induces hyper-reaction of rat to noxious electric stimulus; the decapeptide (OFQ1-10 i.c.v.), a fragment of the OFQ, did not affect the pain reaction of rats. Fentanyl (1 microgram, i.c.v. or i.t.h.), a selective mu-receptor agonist, DSLET (5 micrograms, i.c.v. or i.t.h.), a selective delta-receptor agonist, or U50488H (1 microgram, i.t.h.), a kappa-receptor agonist, induced an increase in pain threshold, when OFQ (0.1 or 1 microgram) was added together with one of them (except for the ith injection of DSLET), the increase of pain threshold was reduced obviously.

CONCLUSION

OFQ induces hyperalgesia and antagonizes opioid analgesia mediated by mu- and delta-receptors in the brain and by mu- and kappa- but not delta-receptors in the spinal cord of rats.

Orphanin FQ potentiates formalin-induced pain behavior and antagonizes morphine analgesia in rats

The present study was designed to observe the effect of orphanin FQ (OFQ, also known as 'nociceptin'), a newly-discovered neuropeptide, on pain behavior and morphine analgesia evaluated by formalin test in rats. It was found that intracerebroventricular (i.c.v.) injection of 0.1 microg OFQ had no effect on formalin-induced pain behavior; but 1, 5, 10 or 20 microg OFQ produced prolonged lifting, licking, biting or shaking of the affected paw with higher pain scoring in dose dependent manner. Repeated i.c.v. injection of antisense olignucleotide (ASO) complementary to OFQ receptor but not mismatch olignucleotide (MSO) resulted in the decrease of pain behavior; in such circumstances, OFQ showed no enhancing effect on formalin nociception. OFQ (0.1 or 1 microg, i.c.v.) significantly attenuated morphine analgesia and ASO could validly antagonize the effect of it. Pretreatment with MSO had no such effect. The present results suggest that OFQ enhances the pain behavior of rat and antagonizes morphine analgesia in formalin test.

[Effect of intrathecal or intracerebroventricular administrition of OFQ on pain threshold and acpuncture analgesia in rats]

Orphanin FQ (OFQ) is a newly discovered 17-amino-acid peptide capable of inducing hyperalgesia. In the present study, the effects of OFQ on basal pain threshold and acupuncture anlgesia (AA) in rats were observed using the tail-flick test. It was found that intrathecal (i.t.) or intracerebroventricular (i.c.v.) administrition of 0.1 microgram OFQ had no effect on basal pain threshold of rats, while 1 microgram OFQ could lower the threshold. However, OFQ at both the doses (0.1 or 1.0 microgram) administered by either i.t. or i.c.v. injection could antagonize AA with that occuring in the brain being more prominent then in the spinal cord. When the rats were repeatedly treated with antisense oligonucleotide to block synthesis of OFQ receptor, pain threshold increased significantly. At such instance, when the OFQ was combined with acupuncture, the effect of AA showed no obvious change. The above results show that the OFQ at small dose has no effect on pain threshold but can lower it at larger dose; while in both cases OFQ can antagonize AA.

Expression of preproopiomelanocortin mRNA and preprodynorphin mRNA in brain of spontaneously hypertensive rats

AIM

To compare the expressions of prepropiomelanocortin (POMC) mRNA and preprodynorphin (PPD) mRNA between 16-wk-old spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto rats (WKY).

METHODS

The expression of POMC mRNA and PPD mRNA were detected with nonradioactive in situ hybridization by digoxigenin-labeled RNA probe.

RESULTS

POMC mRNA mainly was expressed in arcuate nucleus, compared with WKY, SHR had higher level of POMC mRNA (542). PPD mRNA was found in hippocampus, hypothalamus, central gray, nucleus of the solitary tract (NTS), and thoracic spinal cord (T4-T6). Compared with WKY, PPD mRNA level of SHR decreased in dentate gyrus (2342), NTS (381), and medial preoptic area (467); no difference was observed in arcuate nucleus (263), thoracic spinal cord (750-1800) and CA1, CA2, CA3 of hippocampus (1674, 2014, 2626).

CONCLUSION

Increase of POMC mRNA in arcuate nucleus and decrease of PPD mRNA in dentate gyrus of SHR may be associated with the genesis of spontaneous hypertension.

[Alteration of monoamine contents in microdialysate following droperidol enhanced electroacupuncture]

The monoamine contents in microdialysate from rat brain before and after droperidol (DRO), a dopamine (DA) antagonist, enhanced electroacupuncture-induced analgesia (EA) were measured using techniques of in vivo microdialysis and high performance liquid chromatography with electrochemical detection (HPLC-EC), so as to investigate the monoamine mechanism of the potentiating effect of DRO on acupuncture analgesia (AA). The results showed that the levels of DA and its metabolites homovanillic acid (HVA) in perfusate increased after EA (P < 0.05 or 0.01), and further increased after DRO + EA (P < 0.05 and 0.01, vs EA treatment). A significant decrease in norepinephrine (NE) content after EA (P < 0.01) was observed, but no further change after DRO + EA (P > 0.05, vs EA treatment). The contents of 5-hydroxytryptamine (5-HT) and its metabolite 5-hydroxyindole acetic acid (5-HIAA) we elevated after EA treatment, and a further elevation in 5-HT and 5-HIAA contents induced by DRO + EA was noted. The results in the present study suggest that DRO potentiated AA not only via antagonizing the activity of dopaminergic system, but also by coordinating the activities of other monoamines in the brain.

Autologous bone marrow mixed with HLA-haploidentical allogeneic marrow transplantation for treatment of patients with malignant blood diseases

We have previously demonstrated that syngeneic marrow mixed with H-2 haploidentical marrow transplantation could provide not only protection against graft-versus-host disease (GVHD) but also anti-leukemic (GVL) effects in mice. In the present studies, we report clinical observations using autologous marrow mixed with HLA-haploidentical allogeneic marrow transplantation for treatment of patients with malignant blood diseases. Sixteen cases, including 12 with acute leukemia and four with advanced malignant lymphoma, were treated by autologous marrow, which was purged in vitro by hyperthemia (42.5 degrees C for 70 min) following incubation for 5 days with interleukin 2 (IL-2) in liquid culture and mixed with HLA haploidentical marrow cells from their sibling or parent. Acute GVHD was not observed in any patient after transplantation. Hematological rescue in the clinical setting was demonstrated in all cases but one who died early from hepatic veno-occlusive disease (VOD). Five cases who were transplanted at the time of CR2 or CR3 and in advanced phase of lymphoma, relapsed 4 to 7 months after transplantation. The relapse rate was 31.3%. None of eight patients who received allogeneic BMT within 2 h after ABMT relapsed with median follow-up of 12 months and two of them died from procedure-related complications. Seven cases are still alive and disease-free with a median follow-up of 12 months. Mixed chimerism was found in 3/6 cases, who had different sex donors, by analysis of sex chromosomes. These results show that mixed transplantation is a safe, effective and new approach to treating patients with malignant tumors. In order to detect the effects of GVL, studies are now in progress in our clinic.

Preproopiomelanocortin and preprodynorphin mRNA expressions in rat brain after electroacupuncture + droperidol

AIM

To study the expression of preproopiomelanocortin (POMC) and preprodynorphin (PPD) mRNA following the combination of electroacupuncture (EA) with droperidol (Dro), a dopamine receptor antagonist.

METHODS

The brains and spinal cords of Sprague-Dawley rats were sectioned after combination of EA with Dro, and the gene expression was investigated using nonradioactive in situ hybridization histochemistry (ISHH).

RESULTS

Ten hours after EA, the POMC mRNA expression was enhanced; the expression was further enhanced when EA was combined with Dro. The expression of PPD mRNA showed regional difference in central nervous system (CNS): in spinal cord, EA enhanced the PPD mRNA expression and the combination of EA with Dro further promoted the expression; in the brain, the PPD mRNA expression after EA or combination of EA with Dro showed no obvious change in most regions (caudate-putamen, accumbens, arcuate nucleus of hypothalamus) or was decreased in supraoptic nucleus.

CONCLUSION

Dro combined with EA promoted the expression of POMC mRNA in CNS and PPD mRNA in spinal cord, but reduced or had no effect on PPD mRNA expression in the brain.

Antagonistic action of orphanin FQ on acupuncture analgesia in rat brain

The influence of orphanin FQ (OFQ) (a newly discovered 17-amino acid peptide) on acupuncture analgesia (AA) was assessed in rat tail-flick model. Intracerebroventricular (i.c.v.) injection of OFQ (1 microgram) elicited a significant decrement of pain threshold which was abolished by the repeated pretreatment with antisense oligonucleotide (ASO) to OFQ receptor. Electroacupuncture (EA) induced an obvious analgesic effect; when OFQ was used combined with EA, it showed a dose-dependent effect on antagonizing the EA analgesia. When rat was repeatedly i.c.v. injected with ASO to block the synthesis of OFQ receptor, the EA analgesia was enhanced markedly. In this instance, the OFQ did not show antagonistic effect on EA analgesia any more. The results suggest that the OFQ play its antagonistic role on EA analgesia via activating OFQ receptor.

Effect of phencyclidine on dog coronary artery

AIM

To study the effect of phencyclidine (Phe) on dog coronary artery.

METHODS

Contraction of spiral strips of dog coronary artery in bioassay and coronary artery blood flow (CBF) using electromagnetic flowmeter on anesthetized dogs were observed.

RESULTS

Phe 0.1-100 mumol.L-1 induced contraction of strips in a concentration-dependent manner. Dextromethorphan (Dex) 10 mumol.L-1, an antagonist of Phe receptor, antagonized the action of Phe. In vivo, Phe 10 mg.kg-1 increased flow of left circumflex coronary artery of anesthetized dogs from 334 +/- 35 mL.kg-1.min-1 to 510 +/- 58 mL.kg-1.min-1, and both left ventrical pressure (LVP) and blood pressure (BP) rose slowly after medication. Dextromethorphan (Dex) 5 mg.kg-1 also antagonized the effect of Phe.

CONCLUSION

The regulation of Phe on coronary artery in vivo differs from that in vitro, which may result in the contradictory effects.

Mapping of preproenkephalin mRNA in brain of spontaneously hypertensive rats

AIM

To detect different expression of preproenkephalin mRNA (PPE mRNA) in 16-wk-old spontaneously hypertensive rat (SHR) and age-matched normotensive Wistar-Kyoto rat (WKY).

METHODS

Nonradioactive in situ hybridization was performed using digoxigenin-labeled RNA probe.

RESULTS

Compared with WKY rats, PPE mRNA levels of 16-wk-old SHR increased in hypothalamic nuclei (> 20), amygdaloid nuclei (> 23), ventrolateral central gray (21.2), reticular substantia nigra (21.5), interpeduncular nuclei (> 21), nucleus of the solitary tract (30.7), rostroventrolateral reticular nucleus (29.1), gigantocellular reticular nucleus (23.9) and thoracic spinal cord (> 30); decreased in dorsal central gray (22.7). No difference was found in compact substantia nigra (22.8), dentate gyrus (26.2) and CA1, CA2, CA3 of hippocampus (> 25).

CONCLUSION

PPE mRNA in brain regions involved in modulation of blood pressure may be associated with the genesis of spontaneous hypertension in SHR. Enkephalin, an endogenous ligand of opioid receptors, is important in the regulation of blood pressure (BP). Intracerebroventricular injection (icv) of mu agonist [D-Ala2-MePhe4-Gly5-ol]-enkephalin (DAGO) and delta agonist [D-Ala2, D-Leu5]-enkephalin (DADLE) increased the BP[1]. In situ hybridization study showed preproenkephalin mRNA was localized in hypothalamic nuclei, hippocampus, NTS, and spinal cord[2], where the cardiovascular regulation took place. The icv of mu agonist morphiceptin induced a pressor response in SHR but hypotension in WKY rat, and delta agonist Tyr-D-Thr-Gly-Phe-Leu-Thr (DTLET) icv decreased BP in SHR but increased BP in WKY[3]. Compared with WKY rats, SHR had greater concentration of methionine-enkephalin (Met-Enk) in cortex, pons, and medulla[4], but lower Leu-Enk in suprachiasmatic nucleus[5]. These studies imply that opiate system is disturbed in essential hypertension. The aim of this study is to determine whether the biosynthetic activity of CNS opiates in brain is altered in case of essential hypertension.

Distributions of mu and delta opioid receptors in central nervous system of SHR rats and normotensive WKY rats

AIM

To compare the distributions of opioid receptor subtypes in central nervous system of spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) rat.

METHODS

[3H] Ohmefentanyl (OMF), [3H]N-methyl-N-[7-(I-pyrrolidinyl)-1-oxaspiro (4,5)dec-8-yl] benzeneacetamide (U-69593) and [3H]etorphine after suppression of mu and kappa-sites by 15 mumol.L-1 each of unlabeled OMF and trans-(1R,2R)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl) cyclohexyl]-benzeneacetamide hydrochloride (U-50 488H) were used as ligands for mu, kappa, and delta opioid receptor subtypes in autoradiography, respectively.

RESULTS

Delta receptors had an increase in hypothalamic nuclei, periaqueductal gray, caudate and interpeduncular nuclei, and a decrease in substantia nigra in SHR than in those of WKY rat. Mu receptors were less concentrated in basolateral amygdaloid nucleus, habenular nuclei and nucleus of solitary tract of SHR than in those of WKY rats. Kappa receptor density was not checked out in the present study.

CONCLUSION

Distribution of opioid receptor subtypes is related to hypertension of SHR, and delta opioid receptor is more important than mu opioid receptor in the maintenance of hypertension in SHR.