Effects of diet containing astaxanthin on visual function in healthy individuals: a randomized, double-blind, placebo-controlled, parallel study

Visual display terminal work has increased rapidly in recent years. Loss of visual acuity is an unfortunate associated effect. Here, we performed a randomized, placebo-controlled study in 60 healthy adults. Participants received a diet containing astaxanthin (9 mg/day) or placebo for 6 weeks. Visual acuity, functional visual acuity, and pupil constriction rate were measured before and after visual display terminal work. In participants aged ≥40 years, corrected visual acuity of the dominant eye after visual display terminal work at 6 weeks after intake demonstrated a higher protective effect of astaxanthin in the astaxanthin group vs the control group (p<0.05). In participants aged <40 years, no significant difference was seen between the astaxanthin and control groups. Moreover, no significant difference was found in functional visual acuity and pupil constriction rate between the astaxanthin and control groups. These results suggest astaxanthin reduces oxidative stress caused by visual display terminal work. Age-related reduction in ciliary muscle strength is likely the main detractor of visual acuity. Correspondingly, astaxanthin reduced visual display terminal work-induced visual stress in the middle-aged and elderly. This study was registered in the UMIN-CTR database (UMIN000043089).

Effects of anthocyanin, astaxanthin, and lutein on eye functions: a randomized, double-blind, placebo-controlled study

We examined the effects of a test food containing anthocyanin, astaxanthin, and lutein on the eye function in healthy Japanese adults with eye fatigue after operating visual display terminals. Forty-four subjects were randomly but equally assigned to the active or placebo group. Two active or placebo capsules were taken once daily for 6 weeks. Accommodative function, tear film break-up time, visual acuity, the value of Schirmer's test, macular pigment optical density level, muscle hardness, and a questionnaire were evaluated before and after a 6-week intervention. Each group included 20 subjects in the efficacy analysis. The active group showed a significant improvement in the percentage of pupillary response of an average of both eyes and dominant eye pre- and post-visual display terminal operation at 6 weeks compared with the placebo group. Moreover, the active group showed a significant improvement in the scores of "A sensation of trouble in focusing the eyes" and "Difficulty in seeing objects in one's hand and nearby, or fine print" compared with the placebo group between before and after ingestion. Therefore, 6-weeks consumption of the test food inhibited a decrease in the accommodative function caused by visual display terminal operation (UMIN000036989).

The effect of consuming an anthocyanin-containing supplement derived from Bilberry (Vaccinium myrtillus) on eye function: A Randomized, Double-Blind, Placebo-Controlled Parallel Study

Objective: The purpose of this study was to determine the effects of 6-week consumption of anthocyanin-containing supplement on eye function.Methods: This was a randomized, placebo-controlled, double-blind, parallel-group comparison study involving 32 healthy Japanese adults with eye fatigue after using visual display terminals (VDTs). Subjects were randomly allocated into either the active group (bilberry-derived anthocyanin 43.2 mg per capsule) or placebo group using a random number generator. Subjects consumed either one active or placebo capsule once a day for 6 weeks. The primary outcome measured was the change in percentage of pupillary response pre- and post-VDT use, whereas the secondary outcomes were tear film break-up time, Schirmer's value, muscle hardness, and subjective symptoms. Experimental data was analyzed using Student's t-test, the two-way analysis of covariance, or Mann–Whitney U-test.Results: Each group included 15 subjects in the efficacy analysis. The active group showed a significant improvement in the logarithmic conversion values of the percentage of pupillary response (active group: 0.2 ± 0.4, placebo group: 0.0 ± 0.3; P = 0.043) and pupillary response/near point (active group: 0.1 ± 0.4, placebo group: −0.1 ± 0.3; P = 0.049) pre- and post-VDT use at 6 weeks compared with the placebo group in a subgroup analysis per eye. No adverse events were reported.Conclusions: The consumption of the supplement containing anthocyanins extracted from bilberry for 6 weeks inhibited the decrease in the accommodative function caused by oxidative stress due to VDT use.Trial registration: UMIN-CTR: UMIN000037039.Foundation: BGG Japan Co., Ltd. and Arysta Health and Nutrition Sciences Corp. 

Cognitive function improvement with astaxanthin and tocotrienol intake: a randomized, double-blind, placebo-controlled study

We examined the effects of the mixed ingestion of astaxanthin derived from Haematococcus pluvialis and tocotrienols on the cognitive function of healthy Japanese adults who feel a memory decline. Forty-four subjects were randomly but equally assigned to the astaxanthin-tocotrienols or placebo group. An astaxanthin-tocotrienols or placebo capsule was taken once daily before or after breakfast for a 12-week intervention period. The primary outcome was composite memory from the Cognitrax cognitive test, and the secondary outcomes were other cognitive functions and subjective symptoms for memory. Each group included 18 subjects in the efficacy analysis (astaxanthin-tocotrienols group, 55.4 ± 7.9 years; placebo group, 54.6 ± 6.9 years). The astaxanthin-tocotrienols group showed a significant improvement in composite memory and verbal memory in Cognitrax at Δ12 weeks compared with the placebo group. Additionally, the astaxanthin-tocotrienols group showed a significant improvement in the subjective symptom of "During the last week, have you had trouble remembering people's names or the names of things?" compared with the placebo group after 12 weeks. No adverse events were observed in this study. The results demonstrated that taking an astaxanthin-tocotrienols combination improves the composite memory and verbal memory of Japanese adults who feel a memory decline (UMIN 000031758).

Does squalene alter the antioxidant potential of astaxanthin and fucoxanthinol? In vitro evidence in RAW 264.7 cells, a murine macrophage

Astaxanthin (Ax) and fucoxanthin/fucoxanthinol (FuOH) are marine xanthophylls exhibiting anti-oxidant effects. Squalene (SQ) is a triterpenoid and is a precursor of sterols. This study aimed to determine if SQ can improve the effect of Ax/FuOH on lipid peroxidation. RAW 264.7 cells were treated with different concentrations of Ax, FuOH and SQ and corresponding rate of cell survival was noted. In addition,combination groups - Ax + SQ and FuOH + SQ- were also run. Cells treated with Ax, FuOH, SQ, Ax + SQ and FuOH + SQ were stimulated with lipopolysaccharide and lipid hydroperoxides were estimated. Results showed that 5 μM Ax, 2 μM FuOH and 10 μM SQ supported cell survival. In presence of SQ, cell viability improved for higher concentrations of FuOH (5, 10 μM). Lipid hydroperoxides were supressed by Ax, FuOH, Ax + SQ and FUOH +SQ and were significantly lower in Ax + SQ, indicating the synergistic effect of Ax and SQ. To conclude, combination of Ax with SQ enhances its ability to supress lipid peroxidation while with FuOH, SQ attenuates the toxic effect at higher doses. Moreover, this is the first time that the combined effect of SQ and carotenoids has been studied and reported.

Inter-rater reliability of proxy simple symptom assessment scale between physician and nurse: a hospital-based palliative care team setting

Symptom management in palliative care requires reliable symptom assessment. We assessed the inter-rater reliability of a simple proxy symptom-assessment scale using the Japanese version of the Support Team Assessment Schedule (STAS-J) in a hospital-based palliative care team (HPCT) setting. By doing this, we assessed symptoms in a series of consecutive patients at two university hospitals with certified HPCTs within 2 days of referral and 7 days after. A physician and nurse assessed 20 symptoms. In total, 120 patients were assessed within 2 days of referral and 92 patients at 7 days after referral. As a result, we find that the intra-class correlation coefficients were 0.02-0.89 at referral and 0.20-0.92 at 7 days after. The perfect concordance rates were 37-89% at referral and 53-96% at 7 days after. The perfect or +/-1 concordance rates were 71-97% at referral and 73-100% at 7 days after. In conclusion, the symptom item of the STAS-J had high inter-rater reliability.

Communication about the ending of anticancer treatment and transition to palliative care

BACKGROUND

Communication about the ending of anticancer treatment and transition to palliative care is a difficult task for oncologists. The primary aims of this study were to clarify family-reported degree of emotional distress and the necessity for improvement in communication methods when communicating about the ending of anticancer treatment, and to identify factors contributing to the levels of emotional distress and the necessity for improvement.

METHODS

A multi-center questionnaire survey was conducted on 630 bereaved family members of cancer patents who received specialized palliative care in Japan. A total of 318 responses were analyzed (effective response rate, 62%).

RESULTS

Thirty-nine percent of the bereaved family members reported that they were 'very distressed' in receiving information about the ending of anticancer treatment, and 19% reported 'considerable' or 'much' improvement was necessary in the communication methods. High-level emotional distress was significantly associated with younger patient age, female family gender, the experience of the physician stating she/he could do nothing for the patient, the physician's unwillingness to explore their feelings, and prognostic disclosure of definite survival periods without probabilities or ranges. High levels of perceived necessity for improvement in the communication methods were significantly associated with the experience of the physician stating she/he could do nothing for the patient, physicians not explaining treatment goals in specific terms, physicians not pacing the explanation with the state of family preparation, physicians not being knowledgeable about the most advanced treatments, and the atmosphere not being relaxing enough to ask questions.

CONCLUSIONS

In receiving the information about ending anticancer treatment, a considerable number of families experienced high levels of emotional distress and felt a need for improvement of the communication methods. The strategies to alleviate family distress could include: (i) assuring that physicians will do their best to achieve specific goals, without saying that they can do nothing for the patient; (ii) providing information, including estimated prognosis, in careful consideration of families' preparation and the uncertainty for each patient; (iii) exploring families' emotions and providing emotional support; (iv) acquiring knowledge about advanced treatments; and (v) making the atmosphere relaxing enough to allow families to ask questions.

Effects of endothelin-1 and nitric oxide on proliferation of cultured guinea pig bronchial smooth muscle cells

The proliferative effects of endothelin-1 (ET-1), both alone and in combination with epidermal growth factor (EGF), and the effect of nitric oxide (NO) on the cell proliferation were investigated in cultured guinea pig bronchial smooth muscle cells. ET-1 (10-100 nM) alone augmented cell proliferation, and was additive to the effect of EGF (0.48 nM) in a concentration-dependent manner. An ET(A) antagonist, BQ-123 (10 microM), reduced the cell-proliferative effect of ET-1, whereas an ET(B) antagonist, BQ-788 (10 microM), did not influence the effect. A NO donor, SIN-1 (10 nM-1 microM), reduced the cell-proliferative effect of ET-1 in a concentration-dependent manner. The effect of SIN-1 (1 microM) was partly, but significantly, reversed by a soluble guanylyl cyclase inhibitor, ODQ (1 microM). These results suggest that ET-1 acts not only as a co-mitogen with EGF but also as a mitogen alone, and that its action is mediated through activation of ET(A) receptors. Therefore, ET-1 may contribute to airway remodeling, a pathophysiological hallmark of asthma. In addition, NO, which is produced mainly in the airway epithelium and is partly mediated through cGMP-dependent pathway, may reduce the phenomenon.

Evidence for the AT1 subtype of the angiotensin II receptor in the rat submandibular gland

We have characterized angiotensin II (Ang II) receptor subtypes on rat submandibular gland membranes using a radioligand binding assay. [3H]Ang II binding to the membrane fractions exhibited both high (Kd =0.08 nm, Bmax =2.19 fmol/mg protein) and low (Kd =4.19 nm, Bmax = 13.7 fmol/mg protein) affinity. Ang 11, Ang III and saralasin completely displaced the [3H]Ang II binding, whereas CV-11974, an AT1 receptor antagonist and PD123319, an AT2 receptor antagonist maximally displaced up to approximately 87 and 13% of the total binding, respectively. [3H]DuP753 binding to the membrane fractions exhibited a single population of binding site with a Kd of 4.22 nM and Bmax of 3.77 pmol/mg protein. Ang II, Ang III and CV-11974 completely displaced the [3H]DuP753 binding with slope factors near unity, but PD123319 did not. These findings suggest that rat submandibular gland membranes contain predominantly the AT1 receptor subtype.

Activation of protein kinase C induces internalization of the GABA(C) receptors expressed in Xenopus oocytes

In a previous study, we showed that the protein kinase C (PKC) activator 4beta-phorbol 12-myristate 13-acetate (PMA) inhibited the gamma-aminobutyric acid (GABA)-gated currents in Xenopus oocytes expressing human rho1 GABA(C) receptors. To investigate whether the inhibition of currents was due to a decrease in efficacy or in the potency of rho1 GABA(C) receptor, concentration-response curves for GABA were compared before and after PMA treatment. The EC50 concentrations of GABA obtained during the maximally inhibited period were not statistically different from the concentrations obtained before PMA treatment (1.74 +/- 0.33 and 1.45 +/- 0.28 microM, respectively). These results indicate that the inhibition depends on a change in number or conductance of active receptor channels, but not on a change in affinity for GABA. To allow histochemical detection of rho1 GABA(C) receptors, we constructed a receptor tagged at the C-terminal position with human c-myc epitope. Electrophysiologically, the tagged receptors showed almost the same sensitivities for GABA and PMA as those of wild-type rho1 GABA(C) receptors. Immunohistochemistry with anti-myc antibody detected a dense concentration of tagged receptors at the surface area of Xenopus oocytes. Transient exposure to PMA reduced the density of immunofluorescence at the surface area and increased it in the subsurface area. These results suggest that the stimulation of protein kinase C leads to internalization of rho1 GABA(C) receptors expressed in Xenopus oocytes.

Involvement of angiotensin II and endothelin-1 in the development of submandibular gland hypertrophy in response to isoproterenol in rats

We investigated whether angiotensin II (Ang II) and endothelin-1(ET-1) are involved in submandibular hypertrophy in response to repeated treatment with isoproterenol (ISO) in rats. The immunoreactive Ang II (IRAng II) and immunoreactive ET-1 (IRET-1) contents of ISO-induced hypertrophy were significantly higher than those of control glands. Treatment of isolated gland tissues with ISO (1 microM) or dobutamine (1 microM) caused significant increases in the IRAng II and IRET- 1 contents of the glands compared with controls. These increases were suppressed by pretreatment with enalapril (3 microM) or captopril (3 microM). Treatment with Ang II (10 microM) also caused an increase in IRET-1 content. Our findings suggest that Ang II and ET-1 are involved in the submandibular gland hypertrophy that develops in rats repeatedly treated with ISO, and that these biologically active peptides may act as growth factors. They also imply that the tissue renin-angiotensin system and Ang II specific receptors are present in the submandibular glands.

Antigen-induced elevation of immunoreactive endothelin-1 (ET-1) levels in ovalbumin-sensitized guinea pig airway tissue

Changes in the immunoreactive ET-1 levels during the anaphylactic reaction of airway tissue from ovalbumin-sensitized guinea pigs were investigated. ET-1-immunoreactivity (ET-IR) was detected in the epithelial and smooth muscle layers of tracheal sections from normal guinea pigs and it was enhanced slightly by phosphoramidon (1 microM) treatment. The ET-IR level of the epithelial layer of ovalbumin-treated tissue from actively sensitized animals was slightly higher than that from normal animals, but it was enhanced markedly by phosphoramidon (1 microM) treatment. Furthermore, the mean ET-IR level of homogenates of antigen-treated tracheal tissues from sensitized guinea pigs (22.8 +/- 1.55 fmol mg-1 protein, n = 5) was significantly higher than the corresponding normal level (12.3 +/- 1.21 fmol mg-1 protein, n = 5). These results suggest that increased epithelial airway ET-1 levels contribute to the anaphylactic reaction of guinea pig airways.

Consensus phosphorylation sites of human GABA(c)/GABArho receptors are not critical for inhibition by protein kinase C activation

The mechanism of inhibition of human GABA(C)/GABArho receptors by protein kinase C (PKC) activation was investigated in Xenopus oocytes. Phorbol 12-myristate 13 acetate (PMA), a potent PKC activator, at 25 nM inhibited the currents through GABArho2 receptors, which have one consensus phosphorylation site by PKC in the predicted intracellular loops. The time-courses and amplitudes of inhibition were not significantly different from those occurring through GABArho1 receptors, which have six such sites. The inhibitory effect of PMA was also observed after removing each consensus phosphorylation site in both GABArho1 and rho2 receptors by site-directed mutagenesis. These results suggest that phosphorylation of consensus sites in the intracellular loops is not involved in the inhibition of human GABA(C)/GABArho receptors by PKC activation.

Beta-funaltrexamine discriminates between two subtypes of mu2-opioid receptors in electrically stimulated longitudinal muscle of guinea pig ileum

1. Morphine inhibited twitch responses of the longitudinal muscle of the guinea pig to electrical stimulation. A concentration-response curve of morphine was partly inhibited by a 60-min pretreatment of ileal strip with 10(-10) M of beta-funaltrexamine (beta-FNA). However, the 60-min pretreatment with a higher concentration (10(-9) M) of beta-FNA had no further significant inhibitory effect on the curve of morphine, suggesting that beta-FNA discriminated between two subtypes of mu2 receptors, beta-FNA-sensitive and -resistant receptors. 2. The mu2 receptors in synaptosomal fraction were selectively labeled by [3H]naloxone, and the labeled receptors were competitively inhibited by morphine. The competitive-inhibition curve of morphine showed the presence of high- and low-affinity sites. Beta-FNA eliminated the high-affinity site only when endogenous GTP or GTPgamma-S was present. 3. Beta-FNA discriminated between two subtypes of mu2 receptors.

Synergistic actions of pentobarbital and dihydropyridine Ca2+ antagonists on guinea pig isolated thoracic aorta

In order to elucidate the mechanism(s) behind the interactions between barbiturates and Ca2+ antagonists, the effects of pentobarbital combined with three structurally diverse types of Ca2+ antagonist on CaCl2-induced contractile responses of the guinea pig thoracic aorta in Ca(2+)-free and 40 mM K+ medium and the effects of pentobarbital on Ca2+ antagonist binding to guinea pig aortic membranes were investigated. The dihydropyridine derivatives isradipine (10(-10)-10(-8) M) and nifedipine (10(-10)-10(-8) M) inhibited CaCl2-induced contractions concentration-dependently. Treatment with both pentobarbital (10(-4) M) and dihydropyridine Ca2+ antagonists (10(-9) M) shifted the CaCl2 concentration-response curves to the right significantly compared with those after treatment with the Ca2+ antagonists and pentobarbital alone. However, no synergistic effects of pentobarbital (10(-4) M) with other types of Ca2+ antagonist (verapamil (10(-7) M) and diltiazem (10(-6) M)) were observed. The binding of [3H]isradipine (2 x 10(-9) M) to guinea pig aortic membranes was increased significantly by simultaneous pentobarbital treatment, but no such effect was observed with [3H]verapamil (10(-8) M) or [3H]diltiazem (2 x 10(-8) M). These findings suggest that the synergistic contractile effects of pentobarbital and dihydropyridines were, in part, due to enhancement of dihydropyridine binding to guinea pig aortic membranes (L-type Ca2+ channels) by pentobarbital and that the interactions between pentobarbital and Ca2+ antagonists may be structurally specific.

GABA rho1 receptor: inhibition by protein kinase C activators

The effects of protein kinase C (PKC) activators on gamma-aminoburyric acid (GABA) rho 1 receptor function were studied in rho 1 -expressing Xenopus oocytes. The PKC activator phorbol 12-myristate 13-acetate (PMA) but not the inactive analog phorbol 12-mono-myristate inhibited the GABA-gated chloride currents. Mezerein, a non-phorbol ester type PKC activator, also inhibited the rho 1 responses, but 8-chlorophenylthio-cyclic AMP, a protein kinase A activator, had no effect. The effect of PMA was significantly reduced by a PKC inhibitor, staurosporine. These results suggest that GABA rho 1 receptor function can be regulated by PKC-mediated phosphorylation events.

Effects of organic and inorganic Ca(2+)-antagonists on acetylcholine-induced contraction in molluscan (Mytilus edulis) smooth muscle

1. Effect of Ca(2+)-antagonist on the contractile response to acetylcholine (ACh) in molluscan (Mytilus edulis) smooth muscle was investigated. 2. ACh-induced contraction was remarkably reduced by exposure to Ca(2+)-deprived medium. 3. The organic Ca(2+)-blockers, verapamil, diltiazem and nicardipine, reduced the concentration-response curve for ACh in a concentration-dependent manner. 4. The inorganic Ca(2+)-blockers, MnCl2, NiCl2, CoCl2 and CdCl2, also reduced the concentration-response curve for ACh concentration-dependently. 5. ACh significantly increased the amounts of inositol 1,4,5-trisphosphate (IP3) in the ABRM. 6. ACh-induced contraction in the ABRM might therefore be mediated through an influx of extracellular Ca2+ and Ca(2+)-release from IP3 sensitive intracellular pools.

Partial purification and characterization of a polyketide biosynthetic enzyme, 6-hydroxymellein synthase, in elicitor-treated carrot cell extracts

6-Hydroxymellein synthase, an induced polyketide biosynthetic enzyme in carrot cell extracts, was purified about 240-fold and its properties were compared with those of fatty acid synthetases. Synthetic activity of 6-hydroxymellein was inhibited in the presence of sulfhydryl reagents; however, cerulenin, a well-known inhibitor of fatty acid synthetases, showed no inhibitory activity to the enzyme. Biosynthesis of 6-hydroxymellein includes an NADPH-dependent ketoreduction, and, in this reaction, the 4-pro-S-hydrogen of NADPH was specifically transferred to the compound. On the basis of stereochemical analyses of the biosynthetic process, it was concluded that the product of the ketoreduction is an optically active alcohol of R configuration. These stereo-specificities of the reduction process are identical to those of beta-ketoacyl reductase in fatty acid biosynthesis which are considered to be conserved in all organisms. The synthetic rate of 6-hydroxymellein was markedly reduced when the assay was carried out with deuterium-labeled NADPH. The observed isotope effect on the catalytic rate (kH/kD) was 5.20, suggesting that this ketoreduction is one of the rate-limiting processes in 6-hydroxymellein synthesis. More than 85% of the synthetic activity was found in the soluble fraction of carrot cells, and, unlike in fatty acid synthetases in higher plants, organelle-localizing activity was not observed.

Possible site of action of 2-methylserotonin in inducing relaxation of acetylcholine-induced contraction in the molluscan (Mytilus edulis) smooth muscle

1. The present study investigated the presence of 5-HT3 receptor using 2-methylserotonin (2-Me-5-HT) in the smooth muscle of Mytilus ABRM. 2. 2-Me-5-HT relaxed the acetylcholine-induced contraction in a dose-dependent manner ranging from 10(-6) to 3 x 10(-4) M (pD2 = 5.55 +/- 0.32). 3. 2-Me-5-HT-induced relaxation was antagonized by 3 x 10(-5) M ketanserin in a competitive manner (pA2 = 5.14 +/- 0.1), but not by cypropheptadine, mianserin, MDL 72222 or ICS 205-930 at a concentration of 3 x 10(-5) M. 4. 2-Me-5-HT (3 x 10(-4) M) did not alter the content of cyclic AMP and cyclic GMP in the ABRM. 5. These findings suggested that the 2-Me-5-HT-induced relaxation was mediated through 5-HT2-like receptors and was not linked to cyclic AMP or GMP systems, and, further, that 5-HT3 receptor subtype was not present in the ABRM.

Organic Ca(2+)-antagonist-resistant response to FMRF-NH2 on the molluscan smooth muscle

1. FMRF-amide (10(-7)-10(-5) M) contracted molluscan anterior byssus retractor muscle in a concentration-dependent fashion. 2. The concentration-response curve of FMRF-amide was shifted rightward by an analogue of FMRF-amide, FMRf-amide ([D-Phe4]FMRF-amide, putative FMRF-amide receptor antagonist) in a parallel manner (pA2 = 4.87 +/- 0.04). 3. Although a contractile response to KCl was reduced by the organic Ca2+ antagonists (verapamil, diltiazem and high concentration of nifedipine and nicardipine). FMRF-amide-induced contraction was not markedly reduced by them. 4. In the Ca(2+)-free medium, FMRF-amide-induced contraction was diminished. The response was also reduced by TMB-8 (10(-4) M), suggesting that FMRF-amide-induced contraction might be partly dependent on intracellular Ca2+. 5. An inorganic Ca(2+)-antagonist, MnCl2, markedly reduced the FMRF-amide- and KCl-induced contraction. The results show that FMRF-amide-induced contraction might be dependent on extracellular Ca2+. 6. These findings suggest that FMRF-amide-induced contraction might be mediated through an action on FMRF-amide receptors and not through the activation of organic Ca2+ antagonist-sensitive Ca2+ channels.

Effect of ageing on response to nicotine in rabbit bronchial preparation

1. Effect of ageing on the response to nicotine was tested in the bronchial muscle preparations from 5, 13, 100 and 125 week-old rabbits. The pD2 value (potency) of nicotine significantly increased in the preparation from the 125 week-old rabbits. No age-related change was found in the pD2 value of carbamylcholine or pA2 value of atropine. 2. No age-related change in characteristics of nicotine receptors. Choline acetyltransferase activity, the amount of acetylcholine released by nicotine and acetylcholineesterase activity decreased in the preparations from the 125 week-old rabbits. 3. Decrease in the pD2 value of nicotine in the preparation from the older rabbit is due to a decline in choline acetyltransferase activity followed by a reduction in the acetylcholine released, and not to a change in characteristics of nicotine receptors. 4. These results also suggest that enzymes may be influenced more easily with age than drug receptors.

Effect of ageing on nicotine-induced contraction of guinea-pig bronchial preparation

1. Nicotine-induced contraction of bronchial preparations isolated from 3, 6, 10, 50 and 100 week old guinea-pigs were studied. 2. Contractile responses to nicotine were inhibited by hexamethonium and a substance P antagonist but not by atropine or tetrodotoxin, suggesting that the nicotine-contraction was mediated through a release of substance P-like material(s). 3. The pD2 value (potency) of nicotine did not change with age from 3 to 10 weeks but decreased thereafter to 100 weeks, while no age-related change was found in the pD2 value of substance P. The pA2 value of hexamethonium did not change with age, suggesting that the affinity of drugs to nicotine receptors does not change with age. 4. These results suggest that possibility that age-related change in the pD2 value of nicotine is due to a change in the amount of nicotine receptors but not to a change in the affinity of nicotine to its receptors.

Effects of chronic nicotine treatment on nicotinic receptors in the rabbit urinary bladder

Nicotine induced a phasic contraction in the rabbit urinary bladder. The response was abolished by hexamethonium and partially reduced by atropine and capsaicin. Simultaneous atropine and capsaicin treatment did not abolish the contraction. These findings suggest that the response to nicotine is due to acetylcholine, tachykinins, and unknown mediator release. In contrast, nicotine-induced contraction diminished following the chronic nicotine treatment without a change of its pharmacological properties. These results suggest the possibility that chronic nicotine treatment causes a decrease in nicotinic receptor numbers. Therefore, the binding properties of (-)-[3H]nicotine on rabbit urinary detrusor muscle membrane fractions were studied to evaluate the effects of chronic nicotine treatment on nicotinic receptors. Specific (-)-[3H]nicotine binding reached saturation and Scatchard plots were curvilinear, suggesting the existence of two different affinity sites for (-)-[3H]nicotine. Dissociation constants (KD) and maximum binding sites (Bmax) were KD1 = 4.91 +/- 1.88 nM, Bmax1 = 2.42 +/- 0.22 fmol/mg protein and KD2 = 263 +/- 56 nM, Bmax2 = 25.0 +/- 4.3 fmol/mg protein. In urinary bladder membrane fractions from chronic nicotine-treated rabbits, KD and Bmax values were KD1 = 3.96 +/- 0.38 nM, Bmax1 = 1.07 +/- 0.25 fmol/mg protein and KD2 = 249 +/- 12 nM, Bmax2 = 10.8 +/- 1.5 fmol/mg protein. Dissociation constants for both sites following chronic nicotine treatment did not change but maximum binding site numbers for both sites significantly decreased (p less than 0.05). These results suggest that the decrease in contractile response evoked by nicotine after chronic nicotine treatment in rabbit urinary bladder is due to a decrease in numbers of nicotinic receptors.

Derailment product in NADPH-dependent synthesis of a dihydroisocoumarin 6-hydroxymellein by elicitor-treated carrot cell extracts

Synthetic activity of 6-hydroxymellein, the immediate precursor of carrot phytoalexin 6-methoxymellein, from acetyl-CoA and malonyl-CoA was induced in carrot cell extracts when the root disks were treated with CuCl2 or oligogalacturonide elicitor. These elicitors showed specific inducing activity of phytoalexin production and did not affect fatty acid synthesis in carrot tissues which may share some common properties with 6-hydroxymellein biosynthesis. 6-Hydroxymellein production was an NADPH-dependent process and, in the absence of the reagent, triacetic acid lactone was produced as a derailment product of the reaction process. This finding suggested that the reduction of the double bond at the 3,4-position of the phytoalexin takes place during the elongation of the poly(oxomethylene) chain. This NADPH-dependent reduction seems to occur at the triacetate stage before the condensation of the third malonyl-CoA as the conversion of carbonyl to hydroxyl group.

Characterization of nicotine-induced contraction in the canine bronchus

1. The modes of action of nicotine on the dog bronchial smooth muscle preparation was investigated, in order to compare with those on the bronchial preparations from the guinea-pig, rabbit and monkey. 2. Nicotine induced a contraction in the dog bronchial preparation, and this response was abolished by hexamethonium and atropine and potentiated by physostigmine. 3. These findings suggest that the contractile response to nicotine was mediated through an action on the nicotinic receptors and due to the release of acetylcholine. 4. Tetrodotoxin did not inhibit the contractile response to nicotine in the dog bronchial preparation, suggesting that the nicotine-induced response may be produced mainly through a sodium action potential-independent process. 5. The present observations in the dog bronchial preparations coincided with those in the rabbit and monkey bronchi but not with the findings in the guinea-pig bronchus.

Substance P-containing nerves mediate nicotine-induced contractions of rabbit bronchial smooth muscle

1. A possible role of substance P-containing nerves in the contractile response to nicotine was investigated in isolated rabbit bronchial smooth muscle preparation. 2. Nicotine caused a contraction which was attributed to the release of acetylcholine in the rabbit bronchus. The response was reduced by capsaicin (10(-5) M) and a substance P antagonist, [D-Arg1, D-Pro2, D-Trp7.9, Leu11] substance P (10(-5) M). 3. Substance P (10(-7) M)-induced contraction was reduced by atropine (10(-6) M) and potentiated by physostigmine (10(-6) M). Furthermore, substance P (10-7 M) enhanced the release of tritium or acetylcholine from the [3H]choline labelled bronchi. 4. Results suggest that substance P-like tachykinin accelerates the nicotine-evoked prejunctional endogenous neural release of acetylcholine on the nervous cells in the rabbit bronchial preparation.

Pharmacological action of nicotine in the isolated urinary bladder from rabbit: special reference to the chronic nicotine treatment

1. A mode of action of nicotine and a change of the responsiveness to nicotine following chronic nicotine treatment in the urinary bladder of rabbit were investigated. 2. Nicotine induced only a contraction in the urinary bladder of rabbit, and the response to nicotine was reduced by hexamethonium, atropine and capsaicin. These findings suggest that the contractile response to nicotine was mediated through an action on the nicotinic receptors and partially due to the release of acetylcholine and tachykinins. 3. Tetrodotoxin did not inhibit the contractile response to nicotine in the rabbit detrusor muscle, suggesting that the nicotine-induced response may be produced mainly through a sodium action potential-independent process. 4. Nicotine-induced contraction was reduced following the chronic nicotine treatment without a change of its pharmacological properties. These findings suggest that chronic nicotine treatment might cause a decrease of the amounts of nicotinic receptors and also receptors for mediators released by nicotine.

Noncholinergic contractile response to nicotine in the guinea pig isolated tracheal smooth muscle

The existence of substance P immunoreactive nerves in the trachea of guinea pig is known. In this study, capsaicin induced a long-lasting and marked contraction in the guinea pig trachea and nicotine-induced contraction was partially reduced in the capsaicin-treated muscle. Furthermore, the contractile response to nicotine (10(-5) M) in the presence of atropine (10(-7) M) was abolished by a substance P antagonist, [D-Arg1, D-Pro2, D-Trp7,9 Leu11]substance P (10(-5) M). These findings suggest that noncholinergic contractile response to nicotine may be due to the release of material(s) resembling substance P in the isolated tracheal smooth muscle preparation of guinea pig.

(+/-)-1-[[2-(3,4-Dimethoxphenyl)ethyl]amino]-3-(3-methylphenoxy)-2- propanol hydrochloride (bevantolol, NC-1400) as a beta 1-selective adrenoceptor blocker with alpha 1-adrenoceptor blocking activity

Blocking activities of alpha- and beta-adrenoceptors by (+/-)-1-[[2-(3,4-dimethoxyphenyl)-ethyl]amino]-3-(3-methylphenoxy)-2 -propanol hydrochloride (NC-1400) were tested on the isolated muscles, comparing with those of labetalol and atenolol. In blocking the beta 1-adrenoceptor, NC-1400 was slightly more potent than labetalol and atenolol. NC-1400 was about 1/10th as potent as labetalol and about ten times as potent as atenolol in blocking the beta 2-receptor. NC-1400 was beta 1-adrenoceptor selective. NC-1400 was about 1/30th as potent as labetalol in blocking the alpha 1-receptor. NC-1400 did not interact with the alpha 2-adrenoceptor in concentrations up to 10(-5) M. The present results indicate that NC-1400 is the selective beta 1-adrenoceptor blocker with some blocking activity of alpha 1-adrenoceptors.

Actions of 4-(2-hydroxy-3-[(1-methyl-3-phenylpropyl)amino]propoxy) benzeneacetamide (KF4317) and labetalol on alpha- and beta-adrenoceptors

Blocking activities of alpha- and beta-adrenoceptors by 4-(2-hydroxy-3-[(1-methyl-3-phenylpropyl)amino]propoxy)benzeneacetamide (KF4317) were tested on the isolated muscles, compared with the action of labetalol. In blocking the beta 1-adrenoceptor, KF4317 was almost as active as labetalol. KF4317 was about 1/10th as potent as labetalol in blocking the beta 2-receptor. KF4317 was beta 1-adrenoceptor selective. KF4317 was about 1/50th as potent as labetalol in blocking the alpha 1-receptor. KF4317 did not interact with the alpha 2-adrenoceptor in concentrations up to 10(-5) M. The present results indicate that KF4317 is a selective beta 1- and alpha 1-adrenoceptor blocker, though the alpha 1-adrenoceptor blocking action is weak.

Mechanism of action of nicotine on crab-eating monkey isolated bronchial smooth muscle

Monkey (crab-eating monkey) was used as an experimental animal in this study since the pharmacological properties of isolated monkey bronchial smooth muscle were reported to be qualitatively similar to human muscle. Nicotine (10(-5)-10(-3) M) induced a phasic contraction in the isolated monkey bronchial smooth muscle preparation. The contractile response to nicotine was abolished by hexamethonium and atropine and potentiated by physostigmine but not influenced by tetrodotoxin. These results suggest that the response to nicotine was mediated through the release of acetylcholine, and that the nicotine-induced response may be produced through a sodium action potential independent process. In addition, the mechanisms of action of nicotine on the bronchial preparation of crab-eating monkey were similar to those of nicotine on the rabbit bronchial preparation but not to those on the isolated guinea-pig bronchus.

Possible involvement of substance P immunoreactive nerves in the mediation of nicotine-induced contractile responses in isolated guinea pig bronchus

Nicotine-induced contraction of the isolated guinea pig bronchial preparation was abolished by capsaicin and a substance P (SP) antagonist [( D-Arg1,D-Pro2,D-Trp7,9,Leu11]SP). Nicotine increased the release of immunoreactive SP from the preparations. The nicotine-evoked release of immunoreactive SP from the bronchial preparation was reduced by hexamethonium but not by tetrodotoxin. The results indicate that the responses to nicotine of the guinea pig bronchial preparation were mediated through the release of SP-like material(s), and that the nicotine-induced response may be produced through a process independent of the sodium action potential. In conclusion, the most likely site of action of nicotine in the isolated guinea pig bronchial preparation is the nicotinic receptor of SP immunoreactive nerves.

Tetrodotoxin-resistant response to nicotine in rabbit bronchial preparation

The mode of action of nicotine was studied in a rabbit bronchial preparation. Nicotine (3 X 10(-5)-10(-3) M) produced a phasic contraction. No inhibitory response to nicotine was observed. The contractile response to nicotine was inhibited by hexamethonium, pentolinium and atropine but not by tetrodotoxin. Nicotine increased the efflux of tritium from preparations which had been labelled with [3H]choline. Tetrodotoxin did not inhibit the nicotine-evoked tritium release from the bronchial preparation. The results indicate that the release of acetylcholine evoked by nicotine was not influenced by tetrodotoxin in this preparation, and that the nicotine-induced response may be produced mainly through a sodium action potential-independent process. We could not rule out a contribution by acetylcholine released from the acetylcholine store in the smooth muscle in the contractile mechanisms for nicotine.

Nicotinic stimulant, DMPP(1,1-dimethyl-4-phenylpiperazinium iodide) on the isolated bronchial smooth muscle preparation of guinea-pig

Contractile responses of the isolated bronchial preparation of guinea-pig to DMPP, a nicotinic stimulant, were inhibited by ganglion blockers but not influenced by atropine, suggesting that DMPP did not bring about a contribution by stimulation of cholinergic ganglion cells. The fact that tetrodotoxin did not influence the response to DMPP suggests that a possible site of action of DMPP is not on the nerve cells.

Action of nicotine on guinea-pig isolated bronchial smooth muscle preparation

In the isolated bronchial preparation of the guinea-pig, nicotine induced a contraction but not a relaxation. The contractile response of the bronchial preparation to nicotine was inhibited by hexamethonium and d-tubocurarine but not influenced by atropine and tetrodotoxin. In the isolated tracheal preparation of the guinea-pig where nicotine stimulated nicotinic receptor in nervous tissues, the contractile response to nicotine as considerably accelerated by the treatment of the guinea-pig with egg-albumin, while the contractile response of the bronchial preparation to nicotine was not influenced by the same treatment. These results suggest that a possible site of action of nicotine in the isolated bronchial preparation is not on the nervous cells but on the smooth muscle cells. However, we could not rule out a contribution by chemical mediators released by nicotine in the contractile mechanisms in the bronchial preparation.

Possible mechanisms of a new type of antispasmodic drug, BTM-1042(cis-(--)-2,3-dihydro-3-(4-methyl-piperazinyl)methyl-2-phenyl-1,5-benzothiazepin-4(5H)-one dihydrochloride)

A newly synthesized compound, BTM-1042 (cis-(--)-2,3-dihydro-3-(4-methyl-piperazinyl)methyl-2-phenyl-1,5-benzothiazepin-4(5H)-one dihydrochloride) depressed the twitch responses of the ileum from guinea pig to electrical stimulation at 0.1 Hz. This inhibitory action of BTM-1042 was not influenced by naloxone, a narcotic antagonist. BTM-1042 proved to be almost as active as atropine on electrically stimulated ileum. BTM-1042 also blocked muscarinic receptors but the potency was about 1/3 of that of atropine. The responses of the ileum of guinea pig to nicotine and 5-hydroxytryptamine also were inhibited by BTM-1042. However, BTM-1042 did not influence the release of transmitters from motor, sympathetic, nonadrenergic inhibitory (or purinergic nerve), noncholinergic excitatory nerves and responses of various smooth muscles mediated through drug receptors, except for the acetylcholine receptor. Spontaneous movement of the unanaesthetized rabbit stomach was dose dependently depressed by BTM-1042 (0.04--0.2 mg/kg, i.v.). The potency ratio for BTM-1042 relative to atropine was 7.4. BTM-1042 is apparently a new type of potent, antispasmodic drug.