Impact of a systematic education model for palliative care in cancer

In clinical practice, pharmacists are continually required to improve their knowledge and expertise; however, the postgraduate education system for professional development cannot be confidently stated to be well established. The establishment of a systematic and multifaceted educational curriculum should be useful to improve home care and pharmacists' contribution; therefore, we developed a curriculum in collaboration with the university faculty of pharmaceutical sciences, department of pharmacy in hospital, and the Fukuoka Pharmaceutical Association. Class topics were extracted from the "Kanwa-Iryou-Yakugaku", edited by the Japanese Society for Pharmaceutical Palliative Care and Sciences. The items are necessary to perform palliative care as a pharmacist. A class schedule of 6 days (24 classes in total) was formulated. Questionnaires on comprehension degree before and after each class were provided to the participants. Comprehension was assessed on a scale of 1 to 10, where "I do not understand at all" was 1 and "I understand enough" was 10. The average recovery rates of questionnaires from each class were 92.6 % and 88.9 % before and after class, respectively. The average number of participants who completely answered the questionnaire before and after class was 45.6; therefore, these data were analyzed. Comprehension degree on each topic had significantly increased after attendance of all classes (p < 0.01). The comprehension degree of participants of the medical science of palliative care did greatly improve. Consequently, it is clear that the standard education model constructed was meaningful for the professional development of pharmacists in palliative care medicine.

Alterations of the p53 tumor-suppressor gene and ki-ras oncogene in human pancreatic cancer-derived cell-lines with different metastatic potential

Alterations of the p53 and Ki-ras genes were examined in 12 human pancreatic cancer-derived cell lines with different metastatic potential. Point mutations of the Ki-ras gene at codon 12 were found in 10 out of 12 cell lines (83%), while abnormalities of the p53 gene were identified in 8 out of 12 cell lines (67%) which included point mutations (n=7) and one base deletion (n=1). The comparison between alterations of the p53 and Ki-ras genes showed that all the 12 cell lines revealed alterations of both genes or one of these genes regardless of the metastatic potential. Further, same alterations of the Ki-ras gene or p53 gene were noted among the cell lines with increased metastatic potential and their parental cell lines. These findings suggest that alterations of the p53 gene, like the Ki-ras gene is a frequent event in pancreatic cancer, and could contribute cooperatively in the oncogenic steps of pancreatic cancer. It is also suggested that the genetic changes of the p53 and Ki-ras genes are not substantially associated with the metastatic potential in pancreatic cancer.

Role of nociceptin and opioid receptor like 1 on entrainment function in the rat suprachiasmatic nucleus

The suprachiasmatic nucleus of the hypothalamus is the master circadian clock in mammals. Phase shifts in circadian locomotor activity occur when an animal is exposed to light during the subjective night. An endogenous ligand of opioid receptor like 1, nociceptin is reported to inhibit light-induced phase shifts in locomotor activity rhythm. However, little is known about the role of opioid receptor like 1 receptors in the entrainment. Therefore, we investigated the involvement opioid receptor like 1 and its endogenous ligand, intnociceptin, in the suprachiasmatic nucleus and in the entrainment of circadian rhythms in rats. In an in vitro experiment, glutamate (1 microM) -induced phase delay of suprachiasmatic nucleus neuronal activity rhythms was inhibited by nociceptin during the early subjective night. An opioid receptor like 1 antagonist, compound B (10 microM), induced a phase delay, and this effect was blocked by nociceptin (10 microM). Moreover, compound B (10 microM) potentiated the glutamate (1 microM) -induced phase delay. Fos expression in the suprachiasmatic nucleus of rats induced by photic stimulation (50 lux, 30 min) during the early subjective night was inhibited by treatment with nociceptin (0.5-10 nM, i.c.v.). The effect of nociceptin (10nM, i.c.v.) was blocked by pretreatment with compound B (30 mg/kg, i.p). In an in vivo experiment, nociceptin significantly inhibited a light-induced (300 lux, 1 h) phase delay of locomotor activity rhythms, and this effect was inhibited by Compound B. Compound B (30 mg/kg, i.p.) significantly potentiated the light-induced phase delay. Nociceptin induced a neuronal firing phase advance (in vitro) and locomotor activity rhythms (in vivo) in the daytime and this effect was blocked by Compound B. These results suggest that opioid receptor like 1 receptors have an inhibitory effect at night, and a facilitative effect in the day, on phase changes.

Role of 5-ht1b receptors in entrainment disorder of otsuka long evans tokushima fatty (oletf) rats

The role of 5-HT1A and 5-HT1B receptors in entrainment function was studied in Otsuka Long Evans Tokushima fatty (OLETF) rats and control Long Evans Tokushima Otsuka (LETO) rats. Light-induced (100 lux, 30 min) Fos expression in the suprachiasmatic nucleus was studied. Light-induced Fos expression was significantly decreased in OLETF rats compared to that in LETO rats. The decrease of light-induced Fos expression in OLETF rats was significantly reversed by pretreatment with the 5-HT1B receptor antagonist, isamoltan (3 mg/kg, i.p.). Simultaneous administration of CGS12066B (5 mg/kg, i.p.), a 5-HT1B agonist, blocked the reversal effect of isamoltan on Fos expression. Fos expression was not changed in LETO rats by pretreatment with isamoltan (3 mg/kg, i.p.). The Fos expression in LETO and OLETF rats was significantly decreased by pretreatment with the 5-HT1A antagonist, WAY-100,635. Phase shifts in locomotor activity paralleled the Fos expression. Light-induced phase shifts of locomotor activity in OLETF rats were significantly smaller than those in LETO rats. The phase shifts were significantly increased by isamoltan (3 mg/kg, i.p.) in OLETF rats. These results suggest that 5-HT1B receptors are involved in the reduced entrainment function of OLETF rats.

Effects of adenosine A1- and A2A-receptor agonists on enhancement of dopamine release from the striatum in methamphetamine-sensitized rats

We report here both adenosine A1- and A2A-receptor agonists inhibit the expression of methamphetamine (MAP)-induced behavioral sensitization in rats. Animals were treated with MAP (1.0 mg/kg, i.p.) every 3 days with a total of 5 administrations. The augmentation of dopamine release from the striatum was demonstrated by MAP re-administration (0.5 mg/kg, i.p.) after 7-day withdrawal by microdialysis. The augmentation of dopamine release was inhibited by pre-treatment not with N6-cyclohexyladenosine (0.01 mg/kg, i.p.) but by with 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxy-amide adenosine (0.1 mg/kg, i.p.). These results suggested that adenosine A1 and A2A receptors play an inhibitory role in sensitization via different mechanisms.

Repeated adenosine pre-treatment potentiates the acute effect of methamphetamine in rats

Adenosine was intraperitoneally (i.p.) injected to Wistar rats every 3 days with a total of 5 administrations. After a 7-day withdrawal, the animals were challenged with methamphetamine (0.5 mg/kg, i.p.). The effect of methamphetamine on locomotor activity was significantly potentiated by repeated adenosine pretreatment. Moreover, methamphetamine-induced dopamine release was also increased in the striatum. Methamphetamine-induced hyperactivity and dopamine release were significantly potentiated by repeated pretreatment of an adenosine A1 agonist, N6-cyclohexyladenosine (0.5 mg/kg, i.p.). These results suggest that the acute effect of methamphetamine is potentiated by repeated pre-treatment of adenosine via adenosine A1 receptors.

[The biological clock mechanism in non-insulin-dependent and insulin-dependent diabetic rats]

The biological clock mechanism was studied in both non-insulin-dependent and insulin-dependent diabetic model rats. Otsuka Long Evans Tokushima Fatty (OLETF) rats were used as a non-insulin-dependent model. Streptozotocin (STZ, 100 mg/kg, i.p.) was administered to 8- to 10-week-old Wistar rats for an insulin-dependent diabetic model. Both young non-diabetic OLETF and STZ-induced diabetic rats needed more days for re-entrainment to a new light-dark cycle than control rats on activity rhythm. In young OLETF rats, dim-light-induced Fos expression (50 and 100 lux) was significantly decreased in the suprachiasmatic nucleus. In diabetic OLETF rats, Fos expression was decreased by the exposure of light at 300 lux. In STZ-induced diabetic rats, Fos expression was also decreased by 300 lux of light. In OLETF rats, the phase delay by glutamate application was significantly smaller than that in control rats on the suprachiasmatic nucleus neuronal (SCN) activity rhythms. On the other hand, the same level of phase delay was observed between control and STZ-induced diabetic rats by glutamate application. These results suggest that entrainment function is disordered in OLETF rats before the onset of hyperglycemia. To clarify the entrainment function of STZ-induced diabetic rats, however, further study is necessary.

Entrainment function in the suprachiasmatic nucleus of streptozotocin-induced diabetic rats

The term for re-entrainment to a new light-dark cycle in streptozotocin (STZ)-induced diabetic rats was significantly longer than that in control rats. In STZ-induced diabetic rats, the same level of phase delay in the suprachiasmatic nucleus neuronal firing rhythm was observed in control rats after glutamate application. Therefore, 5-HT function in the hypothalamus is thought to be decreased in STZ-induced diabetic rats. These results suggest that postsynaptic neuronal function is still maintained in the suprachiasmatic nucleus of STZ-induced diabetic rats. Therefore, 5-HT mechanisms may play an important role in the maintenance of this function.

Roles of adenosine A(1) and A(2A) receptors in the expression and development of methamphetamine-induced sensitization

We studied the effects of adenosine A(1) and A(2A) receptor agonists on the expression and development of methamphetamine-induced sensitization in rats. When animals were treated with the adenosine A(1) receptor agonist, N(6)-cyclohexyladenosine (CHA), along with methamphetamine every 3 days with a total of five administrations, the augmentation of hyperlocomotion by methamphetamine re-administration after 7-day withdrawal (methamphetamine challenge administration) was not inhibited. However, when the adenosine A(2A) receptor agonist, 2-p-(2-carboxyethyl) phenethyl-amino-5'-N-ethylcarboxy-amide adenosine (CGS21680), was administered according to the same schedule, the augmentation was significantly inhibited. On the other hand, when CHA or CGS21680 was administered 30 min before methamphetamine challenge, both drugs dose-dependently inhibited the augmentation of hyperlocomotion. These results suggested that both adenosine A(1) and A(2A) receptors play important roles in the expression of methamphetamine-induced sensitization, and that adenosine A(2A) receptors do so in the development of this sensitization.

Different effects of trypsin inhibitors on intestinal gene expression of secretin and on pancreatic bicarbonate secretion in CCK-A-receptor-deficient rats

The effects of oral administration of two synthetic trypsin inhibitors (camostate and ONO-3403) and soybean trypsin inhibitor (SBTI) on cholecystokinin (CCK), secretin gene expression and pancreatic secretion were examined in CCK-A-receptor-deficient (OLETF) rats. The rats were fed chow containing 0.1% trypsin inhibitors for 7 days. To examine pancreatic secretion, the rats were prepared with cannulae to drain the bile and pancreatic juice separately, a duodenal cannula and an external jugular vein cannula. The animals were maintained in Bollman cages and the experiments were conducted 4 days after surgery. The levels of CCK mRNA were significantly increased by each treatment. The levels of secretin mRNA were significantly increased by camostate and SBTI, but not by ONO-3403. Bicarbonate secretion was significantly increased in rats treated with camostate and ONO-3403, but not SBTI, while protein secretion was not affected by any treatment. These observations suggest that increased bicarbonate secretion produced by synthetic trypsin inhibitors in CCK-A-receptor-deficient rats may not be due to secretin but due to ONO-3403 in the circulation.

Expression of long-term potentiation of the striatum in methamphetamine-sensitized rats

We examined the change of corticostriatal glutamatergic neuronal transmission in striatal slices of methamphetamine (MAP)-sensitized rats in vitro. Tetanic stimulation induced long-term depression (LTD) of the field potential in the striatum of saline-treated rats. However, it induced long-term potentiation (LTP) in the striatum of MAP-sensitized rats. This LTP was significantly suppressed by a N-methyl-D-aspartate (NMDA) receptor antagonist, aminophosphonovaleric acid (APV). These results suggest that LTP is expressed in the striatum of MAP-sensitized rats, and that NMDA receptors are indispensable for the LTP formation.

Expression of N-methyl-D-aspartate receptor-dependent long-term potentiation in the neostriatal neurons in an in vitro slice after ethanol withdrawal of the rat

To examine changes in corticostriatal synaptic transmission in rats with ethanol withdrawal syndrome, intracellular and extracellular responses to subcortical white matter stimulation were recorded in neostriatal slice preparations. The resting membrane potential, input resistance and depolarizing postsynaptic potentials to single cortical white matter stimulation were similar in the neostriatum of naive and ethanol withdrawal rats. Repetitive stimulation of the white matter induced more pronounced N-methyl-D-aspartate receptor-mediated postsynaptic potentials in ethanol withdrawal than naive rat neostriatum. In intracellular recording, tetanic stimulation (50 Hz, 20 s) induced more pronounced post-tetanic potentiation of depolarizing postsynaptic potentials in the neostriatum of ethanol withdrawal than naive rats. However, in extracellular recording, tetanic stimulation induced smaller post-tetanic depression of population spikes in the neostriatum of ethanol withdrawal than naive rats. Tetanic stimulation of the subcortical white matter induced long-term potentiation of postsynaptic potentials and population spikes in the ethanol withdrawal rat neostriatum, while long-term depression was evoked in the naive rat neostriatum. The induction of long-term potentiation was blocked by D-2-amino-5-phosphonovaleric acid or 7-chlorokynurenic acid, N-methyl-D-aspartate receptor antagonists, but not by (RS)-methyl-4-carboxyphenyl-glycine, a metabotropic glutamate receptor antagonist. Dopamine also significantly depressed the induction of long-term potentiation in ethanol withdrawal rat neostriatum and this depressant effect was antagonized by the D2 antagonist L-sulpiride but not by the D1 antagonist SCH23390. These results indicate that the N-methyl-D-aspartate component of the corticostriatal glutamatergic responses, which might be necessary for induction of long-term potentiation, was enhanced in ethanol withdrawal rats. The depression of long-term potentiation induction by activation of D2 receptor suggests that corticostriatal N-methyl-D-aspartate response or intracellular mechanisms involving in the induction of the long-term potentiation can be suppressed by D2 activation and that the D2 effects are inhibited in the neostriatum of ethanol withdrawal rats.

Lowered entrainment function in the suprachiasmatic nucleus of Otsuka Long Evans Tokushima Fatty (OLETF) rats

The entrainment function in the suprachiasmatic nucleus (SCN) of young non-diabetic Otsuka Long Evans Tokushima Fatty (OLETF) rats was studied. OLETF rats significantly needed more days for re-entrainment to a new light-dark cycle than control Long Evans Tokushima Otsuka (LETO) rats. We also assessed Fos expression in the SCN induced by dim light exposure. The number of Fos-immunoreactive cells was significantly decreased in 5- to 13-week-old OLETF rats compared with LETO rats. Moreover, the effect of glutamate on neuronal activity in the SCN of OLETF rats were investigated. In young non-diabetic OLETF rats, the phase delay in the SCN neuronal firing rhythm induced by 1 microM glutamate was significantly less than that in LETO rats. These results suggested that the entrainment function is reduced in OLETF rats before the onset of diabetes.

Vulnerability of synaptic plasticity in the striatum of methamphetamine-sensitized rats

We examined the influence of ischemia on methamphetamine (MAP)-induced behavioral sensitization and enhancement of dopamine (DA) release. After the recovery period of the ischemia operation, rats were treated with MAP (1 mg/kg, i.p.) once daily for 6 consecutive days. Re-administration of MAP (0.5 mg/kg, i.p.) potentiated the increase of locomotor activity after a 3-day withdrawal and the enhancement of DA release from striatal slices after a 6-day withdrawal. The MAP-induced sensitization was impaired by 5 min ischemia. On the other hand, the increase of locomotor activity induced by single MAP (1 mg/kg, i.p.) administration was impaired by 20 min of ischemia. Moreover, in saline-treated rats the increase of DA release from striatal slices induced by MAP (10 microM) application was also impaired by 20 min of ischemia. These results indicate that the neuronal plastic change may be very vulnerable to ischemia in MAP-induced sensitization.

Disappearance of diurnal rhythm of energy expenditure in genetically diabetic obese rats

The daily profile of energy expenditures was examined in the new animal model of genetically diabetic obese rats. The diurnal rhythm was observed at 8 weeks of age, with highest and lowest values for energy consumption per hour observed in the dark and light periods, respectively. However, at 24 weeks of age after the manifestation of noninsulin-dependent diabetes mellitus, the rhythm completely disappeared, but it did not in the control rats.

N-methyl-D-aspartate receptors are indispensable for the formation of long-term potentiation in the rat suprachiasmatic nucleus in vitro

Optic nerve (ON) stimulation caused a postsynaptic field potential in the suprachiasmatic nucleus (SCN) of rat hypothalamic slices. The postsynaptic field potential was suppressed by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA receptor antagonist, in a concentration-dependent manner, but not affected by D-amino-5-phosphonovaleric acid (APV), a competitive NMDA receptor antagonist. Tetanic stimulation to the ON induced long-term potentiation (LTP) in the SCN. Application of APV at 50 microM inhibited the induction of LTP by tetanic stimulation but CNQX at lower dose (5 microM) didn't inhibit it. These results suggest that NMDA receptors are indispensable for the induction of LTP after tetanic stimulation.

Antitumor effect of DX-8951, a novel camptothecin analog, on human pancreatic tumor cells and their CPT-11-resistant variants cultured in vitro and xenografted into nude mice

DX-8951 is a novel water-soluble derivative of camptothecin. We evaluated the effects of DX-8951 on the growth of several pancreatic tumor cell lines in vitro and in vivo. In vitro cytotoxic activity of DX-8951 against SUIT-2 and KP-1N cells, as indicated by IC50 value, was several times more potent than that of SN-38, an active metabolite of CPT-11, and dozens of times more potent than that of SK&F104864 (topotecan). DX-8951 also showed the greatest cytotoxicity against CPT-11-resistant variants, SUIT-2/CPT-11 and KP-1N/CPT-11 cells, and the cross-resistance of these cells to DX-8951 was lower than that to SN-38 and SK&F104864. Topoisomerase I inhibitory activity of DX-8951 was about three-fold stronger than that of SN-38, as measured in crude nuclear extract obtained from SUIT-2 cells. DX-8951 induced DNA fragmentation, a specific feature of apoptosis, in SUIT-2 cells more effectively than SN-38. DX-8951 exhibited potent antitumor effects against SUIT-2 in a solid tumor model and in a liver metastasis model, in which tumor cells were xenografted subcutaneously and intrasplenically, respectively, into nude mice. The in vivo effects were closely similar to or somewhat superior to those of CPT-11. DX-8951 also showed significant antitumor effects against SUIT-2/CPT-11 solid tumors, against which CPT-11 had no effect. These results suggest that, on the basis of its strong antitumor activity and effectiveness against CPT-11-resistant tumors, DX-8951 may be a useful therapeutic agent in the treatment of human cancer. The potent cytotoxicity of DX-8951 may result from strong inhibition of topoisomerase I, which may then trigger apoptotic cell death.

Decreased level of light-induced Fos expression in the suprachiasmatic nucleus of diabetic rats

We assessed light-induced Fos-immunoreactive cells in the suprachiasmatic nucleus of diabetic rats. The number of Fos-immunoreactive cells significantly decreased in diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats as compared with control Long-Evans Tokushima Otsuka (LETO) rats. In contrast there was no decrease in the number of Fos-immunoreactive cells in young OLETF rats which have not yet developed diabetes. Two months after the administration of streptozotocin (STZ) to Wistar rats, the number of Fos-immunoreactive cells significantly decreased, although 1 week after the administration of STZ, the number had not yet changed in these STZ-induced diabetic rats. These results suggest that chronic diabetic (hyperglycemic) conditions may affect the light entraining responses in the suprachiasmatic nucleus (SCN).

The involvement of calmodulin and Ca2+/calmodulin-dependent protein kinase II in the circadian rhythms controlled by the suprachiasmatic nucleus

We investigated the involvement of calmodulin and Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the photic entrainment of circadian rhythms using calmodulin inhibitors such as calmidazolium (CMZ) and trifluoperazine (TFP), and a CaMKII inhibitor, KN-62, in rats. Fos expression in the suprachiasmatic nucleus (SCN) of rats induced by photic stimulation (300 lux, 1 h) during the early subjective night of the rats was inhibited by treatment with CMZ (10 mg/kg i.p.) or TFP (20 mg/kg i.p.) 30 min before photic stimulation. With respect to the neuronal firing rate in the rat SCN slice, KN-62 and CMZ application during the early subjective night attenuated the glutamate (10 microM)-induced phase shift. The present results suggest that calmodulin and CaMKII are involved in the photic entrainment mechanism in the rodent SCN.

Methamphetamine-induced sensitization of dopamine release via a metabotropic glutamate receptor mediated pathway in rat striatal slices

We studied the roles of metabotropic glutamate receptors in methamphetamine (MAP)-induced sensitization of dopamine (DA) release from striatal slices. Rats were first treated with MAP (1 mg/kg, i.p.) once daily for 6 consecutive days. After a 6-day withdrawal, DA release from striatal slices evoked by +/- (-)1-aminocyclopentane-trans-1,3-dicarboxylic acid (trans-ACPD) was measured, trans-ACPD-induced DA release was significantly enhanced in MAP-sensitized rats, but the inactive form of trans-ACPD (1R,3S-ACPD) did not enhance DA release. The active form of trans-ACPD (1S,3R-ACPD) (0.1 mM)-evoked DA release was attenuated by treatment with 0.4 mM RS-alpha-methyl-4-carboxyphenylglycine, a metabotropic glutamate receptor antagonist. The present results suggest that metabotropic glutamate receptors play an important role in expression of MAP-induced sensitization.

Methylcobalamin induces a long-lasting enhancement of the field potential in rat suprachiasmatic nucleus slices

Optic nerve stimulation has been reported to evoke a field potential (FP) in rat suprachiasmatic nucleus (SCN) slices. Methylcobalamin,delta-(5,6-dymethylbenzimidazolyl)-Co-methyl-cobam ide (Me-B12) enhanced this FP and the enhancement lasted more than 1 h after washing out. Maximal enhancement (143.6 +/- 9.8%) was achieved at a concentration of 10 microM. By contrast, cyanocobalamin containing CN- instead of CH3- showed no enhancement of the amplitude in the FP. Me-B12 induced enhancement of FP was strongly blocked by an N-methyl-D-aspartate (NMDA) receptor antagonist, DL-2-amino-5-phosphonovaleric acid (APV). These results indicate that CH3- in the Me-B12 is required to modulate the FP amplitude and the NMDA receptor is involved in the long-lasting FP enhancement induced by Me-B12. The present results suggest that Me-B12 modifies the photic entrainment of the circadian clock in the suprachiasmatic nucleus via an activation of NMDA receptors.

Involvement of 5-HT1A receptor mechanisms in the inhibitory effects of methamphetamine on photic responses in the rodent suprachiasmatic nucleus

We examined the role of serotonin 1A (5-HT1A) receptors in the inhibitory effects of methamphetamine (MA) on photic entrainment to the circadian pacemaker in the suprachiasmatic nucleus (SCN) of rodents. MA inhibited optic nerve stimulation-evoked field potential in the SCN, light-induced Fos expression in the SCN and light-induced phase shift of hamster wheel-running rhythm. NAN-190, a 5-HT1A receptor antagonist, eliminated the inhibitory effects of MA. NAN-190 has also been reported to antagonize alpha 1 adrenergic receptors. However, prazosin, which selectively antagonizes alpha 1 adrenergic receptors, did not affect the inhibitory action of MA on light-induced Fos expression. In addition, parachloroamphetamine, which is known to be a 5-HT releaser, dose-dependently inhibited light-induced phase shift of wheel-running rhythm. These findings suggest that elevation of endogenous 5-HT levels by MA inhibits the photic entraining responses of the circadian pacemaker in the SCN via 5-HT1A receptor stimulation of the 5-HT released by MA.

Enhancement of dopamine release from the striatum through metabotropic glutamate receptor activation in methamphetamine sensitized rats

An intracerebral microdialysis technique was applied to study the effect of metabotropic glutamate receptor (mGluR) agonist on dopamine release in the striatum of methamphetamine (MAP)-sensitized rats. Rats were treated with MAP (1 mg/kg, i.p.) once daily for 6 consecutive days, followed by a 6-day withdrawal. Perfusion of 0.1 mM (1S,3R)-1-aminocyclopentane-trans-1,3-dicarboxylic acid through a microdialysis probe placed in the striatum enhanced the extracellular dopamine level, and induced stereotyped behavior in MAP-sensitized rats. The enhancement of dopamine release and the stereotyped behavior were attenuated by co-perfusion of 0.4 mM RS-alpha-methyl-4-carboxyphenyl-glycine, a mGluR antagonist. The present results suggest that mGluRs may be involved in the expression of MAP-induced sensitization.

Chronic administration of methamphetamine does not affect the suprachiasmatic nucleus-operated circadian pacemaker in rats

The effects of chronic administration of methamphetamine (MAP) on rat locomotor activity rhythm under light-dark (LD) housing and on neuronal activity rhythms from the suprachiasmatic nucleus (SCN) in vitro were investigated. Control rats exhibited an LD-entrained nocturnal locomotor rhythm. The firing rate of SCN neuronal activity was high during the light period and low during the dark period in control normal rats, and peak of firing activity occurred around zeitgeber time (ZT) 6. On the other hand, chronic MAP administration caused various disorganization of locomotor activity rhythms with a long free-running period (25-35 h). Neuronal activity rhythms of the SCN were unaffected by chronic MAP administration, that is, high during the light period and low during the dark period. The present findings suggested that the SCN maintained as a circadian pacemaker even under chronic MAP administration which affected overt rhythms.

Therapy and imaging of pancreatic carcinoma xenografts with radioiodine-labeled chimeric monoclonal antibody A10 and its Fab fragment

Recombinant mouse/human chimeric monoclonal antibody A10 (ch-A10) and its Fab fragment (ch-Fab) react with carcinoembryonic antigen on various gastrointestinal carcinomas. We performed biodistribution studies with 125I-labeled ch-A10 and ch-Fab in an antigen-positive human pancreatic carcinoma (BxPC-3) xenograft model. We also evaluated the anti-tumor effect of 131I-labeled ch-A10, and studied the detection of BxPC-3 xenografts with 123I-labeled ch-Fab in whole body scintigraphy. In comparative biodistribution studies, the tumor uptake of 125I-labeled ch-A10 was significantly greater than that of 125I-labeled ch-Fab 24 h post-injection. However, the tumor-to-blood ratio was 46.8 for ch-Fab at 24 h post-injection, while it was only 1.4 for ch-A10. Microautoradiography studies showed that ch-Fab penetrated more uniformly into the tumor nodules than did ch-A10. In mice given a therapeutic dose of 131I-labeled ch-A10, a significant inhibition of tumor growth was seen, while control 131-I-labeled human IgG did not affect tumor growth. Leukocyte toxicity was observed within 3 weeks after injection of 131I-labeled ch-A10, but leukocyte counts recovered to normal levels at 8 weeks post-injection. In whole-body scintigraphy, clear and rapid tumor imaging was obtained with 200 microCi of 123I-labeled ch-Fab 24 h post-injection. These results suggest that radioiodine-labeled chimeric A10 antibodies could potentially be useful candidates for radioimmunotherapy and radioimmunodetection of pancreatic carcinomas.

Establishment and characterization of pthrp-producing human pancreatic-cancer cell-line

Human pancreatic ductal cell carcinoma cell line, which can secrete parathyroid hormone-related peptide (PTHrP), designated as KP 4, and its daughter cell lines with different PTHrP-secreting activities, termed KP 4-1 and KP 4-2, have been established in tissue culture. KP 4 cells were able to form tumors in nude mice. The absolute production rate of PTHrP in KP 4-1 was 5 to 10 times higher than that in KP 4-2. Similarly, the level of PTHrP mRNA in KP 4-1 was significantly higher than that in KP 4-2. KP 4-2 cells exhibited more rapid growth than KP 4 and KP 4-1 in vitro. Our established cell lines should provide a useful system to study the regulation of PTHrP production and its pathophysiological roles.

Pancreastatin molecular forms in normal human plasma

Circulating molecular forms with pancreastatin (PST)-like immunoreactivity in plasma from normal subjects were examined. An immunoreactive form corresponding to a human PST-like sequence [human chromogranin-A-(250-301)] (hPST-52) and a larger form (mol wt 15-21 kDa) were detected by gel filtration of plasma from normal subjects. On high performance liquid chromatography, predominant immunoreactive forms coeluted with the three larger forms which were purified from the xenograft of human pancreatic islet cell carcinoma cell line QGP-1N cells and with synthetic hPST-52. The fraction containing larger forms purified from xenograft of QGP-1N cells had biological activity equivalent to that of hPST-52 on the inhibition of pancreatic exocrine secretion. These results suggest that the larger molecular forms as well as hPST-52 may be physiologically important circulating forms of PST in human.

Camptothecin analog (CPT-11)-sensitive human pancreatic tumor cell line QGP-1N shows resistance to SN-38, an active metabolite of CPT-11

In the course of our study to determine the cross-sensitivity between CPT-11 and its active metabolite, SN-38, we found a SN-38-resistant human pancreatic tumor cell line, QGP-1N, which shows sensitivity to CPT-11. The IC50 of SN-38 was 152 times greater for QGP-1N than for SUIT-2, also a human pancreatic tumor cell line, whose IC50 of CPT-11 was similar to that for QGP-1N. The uptakes of CPT-11 and SN-38 and the intracellular conversion of CPT-11 to SN-38 could not explain the difference in sensitivity. DNA synthesis of QGP-1N cells was inhibited by CPT-11 which did not affect that of SUIT-2, while SN-38 inhibited the DNA synthesis of SUIT-2 at lower concentrations than that of QGP-1N. The inhibition test of topoisomerase I catalytic activity by CPT-11 or SN-38 revealed no difference in the biochemical properties of the topoisomerase I enzymes to the compounds between these two cell lines. These results indicate that CPT-11 should have its own inhibitory effect on DNA synthesis through a yet unknown mechanism in QGP-1N cells, although SN-38 plays an essential role in the antitumor activity of CPT-11 in SUIT-2 cells. In some cases, the antitumor effect of CPT-11 might be consequent not only on SN-38 but also on CPT-11 itself.

[Effects of UFT and loxiglumide (CR1505) on liver metastasis of human pancreatic cancer cell line, KP-1 N in nude mice]

Effects of caerulein (CCK), 5-FU and CCK antagonist, loxiglumide (CR1505), were studied on the growth of human pancreatic cancer cell line, KP-1 N, in vitro. And effects of UFT and CR 1505 were also studied on liver metastasis in nude mice. The growth of KP-1 N was stimulated approximately 40% by addition of 10(-10) M of CCK in vitro. CR1505 antagonized the action of CCK, that is, the 40% growth rate increase was suppressed by addition of 25 microM of CR1505. Moreover, the growth rate of the cells dose-dependently decreased by the addition of CR1505. 5-FU also dose-dependently inhibited the growth of KP-1 N in culture. 5-FU additionally decreased the growth rate of KP-1 N in combination with CR1505. A number of metastatic nodules were found in the liver of nude mice a month after injections of KP-1 N cells into the spleen CR1505 suppressed the liver metastasis in nude mice which were administered with UFT. These results suggest that CR1505 would be useful for the treatment of human pancreatic cancer in combination with UFT.

Differential expression of DNA topoisomerase I gene between CPT-11 acquired- and native-resistant human pancreatic tumor cell lines: detected by RNA/PCR-based quantitation assay

RNA/PCR quantitation method was developed to determine DNA Topoisomerase I(Topo I)-specific mRNA in order to study its gene expression in CPT-11 sensitive, acquired- or native-resistant human pancreatic tumor cell lines. The results were supported by Northern blotting and Western blotting analyses. Acquired-resistant cells have shown decreased levels of Topo I mRNA, compared with their parental cells. On the contrary, in the wild type cells no correlation was shown between sensitivity and gene expression. On the other, specific Topo I activity of the native resistant cell lines was fairly lower than that of sensitive cell lines, suggesting that immunoreactive Topo I protein contains low levels of active form enzyme which could be targets of CPT-11 in these native-resistant ones. Finally, the different mechanisms might be operative between acquired- and native-resistant tumor cells.

[Behavioral pharmacological properties of the novel antidepressant paroxetine, a selective 5-HT uptake inhibitor]

The behavioral effects of paroxetine were investigated in mice and rats in comparison with imipramine and amitriptyline. 1) Locomotor activities were decreased by imipramine and amitriptyline but not by paroxetine in both animal species. 2) Paroxetine antagonized methamphetamine-induced hyperactivity in mice as did imipramine and amitriptyline. 3) Paroxetine showed a more potent antimuricidal effect in raphe-lesioned rats than imipramine and amitriptyline, and it also inhibited muricide in olfactory bulbectomized rats. 4) The immobility of rats in the forced swimming test was markedly decreased by imipramine and amitriptyline, but only slightly by paroxetine. 5) Like imipramine and amitriptyline, paroxetine potentiated the methamphetamine- or L-DOPA-induced stereotyped sniffing, and it inhibited oxotremorine-induced tremor. 6) Paroxetine antagonized reserpine-induced hypothermia, tetrabenazine-induced ptosis, and enhanced ether-induced anesthesia, all less potently than imipramine and amitriptyline. 7) The analgesic action of paroxetine was stronger than that of imipramine and amitriptyline. 8) Paroxetine did not antagonize maximal electroshock- or pentetrazol-induced convulsions and haloperidol- or THC-induced catalepsy in rats. In addition, paroxetine neither exerted muscle relaxation nor affected the shuttle-box type conditioned avoidance in rats. From these results, the behavioral effects of paroxetine, as compared with imipramine and amitriptyline, were characterized by its potent antimuricidal action in raphe-lesioned rats and its weak effect in the forced swimming test and by its less potent muscle relaxant, anticonvulsant, anticataleptic and anesthesia-potentiating actions.

[Behavioral effects of quinupramine, a new tricyclic antidepressant]

The effects of a new tricyclic antidepressant quinupramine (5-(3-quinuclidinyl)-10,11-dihydro-5H-dibenz [b, f] azepine) on various animal behaviors were examined in mice and rats and compared with those of imipramine, amitriptyline and maprotiline. Quinupramine antagonized haloperidol-induced catalepsy and tetrabenazine-induced ptosis and potentiated methamphetamine- and apomorphine-induced stereotyped behavior. These effects were almost the same as or even more potent than those of imipramine and amitriptyline. Quinupramine decreased locomotor activity in mice, but potentiated methamphetamine-induced hyperactivity to a greater degree than imipramine and amitriptyline. On the other hand, quinupramine inhibited muricide in accumbens-lesioned rats, but did not prominently inhibit muricide in olfactory-bulbectomized and raphe-lesioned rats. Quinupramine decreased the duration of immobility in low doses without affecting locomotor activity, and this effect was almost the same as that of imipramine and amitriptyline and more potent than that of maprotiline. Quinupramine antagonized physostigmine lethality and oxotremorine-induced tremor, suggesting that quinupramine has a central anticholinergic action. Quinupramine, like imipramine and amitriptyline, has no effect on conditioned avoidance behavior. In conclusion, quinupramine generally has the same behavioral profile as typical tricyclic antidepressants, but it has somewhat different effects from imipramine and amitriptyline since quinupramine has a potent central anticholinergic and a weak antimuricide effect.

Involvement of the medial amygdaloid nucleus in the action of imipramine in rats subjected to the forced swimming test

A forced swimming test proposed by Porsolt is a useful method for screening antidepressants. To evaluate drug effects more objectively, vibration of the walls of a water tank caused by the escape behavior of the rat was recorded. Imipramine (IMI) increased the number of vibration and this effect was observed in the medial amygdala lesioned rat but not in the central or basolateral amygdala lesioned rat. The present result suggests that the medial amygdala is an important site of action of IMI.

A new forced swimming test for the evaluation of antidepressants in rats by recording vibration of a water tank

In order to more objectively evaluate drug effects in the forced swimming test proposed by Porsolt et al. as a screening method for antidepressants, vibrations of the wall of a tank caused by rats trying to escape from water were recorded. Locomotor activity was also measured in an activity cage. Male Wistar rats were forced to swim once daily for 15 min in a tank of 25 degrees C water filled to a depth of 20 cm. After 4 d sessions of swimming, drugs were administered i.p. 3 times (24, 5 and 1 h prior to the test session). On day 5, 45 min after the last injection of a test drug, locomotor activity was measured for 15 min and then the rat was subjected to the forced swimming test. All antidepressants tested, dose-dependently increased tank vibration. Nomifensine, atropine, methamphetamine, chlorpheniramine and diazepam increased locomotor activity. The remaining drugs had no effect or reduced locomotion. In addition, the pattern of the tank vibrations, caused by rats treated with most drugs, like atropine, showed a burst during the first 5 min followed by sporadic vibrations. Nomifensine and methamphetamine, on the other hand, caused vibrations throughout the 15 min test session. A specific effect of antidepressants was revealed by this forced swimming test in combination with the measurement of locomotor activity.

Behavioral and electroencephalographic effects of zopiclone, a cyclopyrrolone derivative

Behavioral effects of zopiclone were investigated in mice and rats and compared with the data on diazepam, nitrazepam and flurazepam. The electroencephalographic effect of the drug was also examined in unanesthetized rabbits with chronic electrode implants and compared with that of diazepam. The present results indicate that zopiclone possesses pharmacological properties qualitatively similar to benzodiazepines, which are characterized by potent anticonflict and antiaggressive effects and much weaker anticonvulsant, muscle relaxant, ataxiogenic, sedative and anesthesia potentiating effects; the properties of this drug were compared with those of diazepam, nitrazepam and flurazepam. Zopiclone suppressed the EEG arousal responses and inhibited afterdischarges induced by electrical stimulation of the hippocampus and amygdala. The effects of zopiclone on EEG and afterdischarges were approximately 1/10 those of diazepam.

delta 9-Tetrahydrocannabinol elicited ipsilateral circling behavior in rats with unilateral nigral lesion

The present study was designed to examine the influence of delta 9-tetrahydrocannabinol (THC) on the central dopaminergic system using circling behavior. THC 5 mg/kg i.p. produced ipsilateral circling in rats with unilateral nigral lesion by 6-hydroxy-dopamine. THC-induced ipsilateral circling was completely antagonized by 0.2 mg/kg of haloperidol. These findings suggest that THC may cause a presynaptic stimulation of nigrostriatal dopaminergic neurons.

[Behavioral pharmacology of amantadine with special references to the effect on abnormal behavior in mice and rats]

Behavioral effects of amantadine, especially on abnormal behavior in mice and rats, were reevaluated, in comparison with those of tricyclic antidepressants, methamphetamine and L-DOPA. 1) Amantadine at 10 approximately 50 mg/kg, i.p., tended to decrease ambulation and rearing in rats and mice. The drug at 50 mg/kg, i.p., caused piloerection and hyperirritability and at doses over 80 mg/kg, i.p., it impaired coordinated motor activity in rats. 2) Amantadine inhibited methamphetamine-induced hyperactivity, but apomorphine-induced stereotyped behavior was unaffected in rats. 3) Amantadine was equipotent to imipramine in suppressing haloperidol-induced catalepsy in rats, but L-DOPA was without effect. On the other hand, amantadine was 40 and 400 times as potent as imipramine and L-DOPA, respectively, in suppressing delta 9-tetrahydrocannabinol (THC)-induced catalepsy in rats. 4) Amantadine was as potent as imipramine in suppressing the muricide of olfactory bulbectomized rats, but was 3.5, 8.8 and 225.5 times as potent as methamphetamine, imipramine and L-DOPA, respectively, in inhibiting THC-induced reversible muricide in rats. 5) Amantadine at 50 mg/kg did not elicit circling behavior in the rat with unilateral nigral lesion induced by 6-hydroxydopamine. 6) Amantadine at high doses caused irritable aggression characterized by squealing in rats pretreated with intraventricular 6-hydroxydopamine. The most important characteristic of amantadine is its prominent effect suppressing the THC-induced catalepsy and muricide. This may be a reflection of the feature of amantadine activating the dopaminergic as well as the serotonergic systems.