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Notes: Abstract: Substance P (SP) and SP analogues, including C-terminal, N-terminal, and C-terminus-extended analogues, have been investigated for their ability to modulate nicotine-induced secretion from bovine adrenal chromaffin cells in culture. Secretion was monitored by measuring the release of endogenous catecholamines by electrochemical detection following separation on HPLC and the release of endogenous ATP with an on-line luciferin-luciferase bioluminescence technique. SP is known to have the following two effects on nicotine-induced secretion of catecholamines (see Livett and Zhou, 1991): inhibition of the nicotinic response and protection against nicotinic desensitization. Secretion induced by 10-5M nicotine was inhibited 70-80% by SP, SP-methyl ester, and the C-terminus-extended analogue SP-Tyr12-NH2, 65% by (Ala3)SP-NH2, 45% by the C-terminal analogue SP(4-11), and 20 and 5% by the N-terminal analogues SP(1-7) and SP(1-5), respectively, when these peptides were present at 3 ×; 10-5M concentrations. The order of potency was SP = SP-methyl ester = SP-Tyr12-NH2 〉 (Ala3)SP-NH2 〉 SP(4-11) 〉 SP(1-7) 〉 SP(1-5). SP, SP-methyl ester, and (Ala3)SP-NH2 protected against nicotinic desensitization by 40-55%, and SP(4-11) protected by 20% (all at 3 ×; 10-5M). In contrast, the N-terminal analogues SP(1-7) and SP(1-5) and the C-terminus-extended analogue SP-Tyr12-NH2 at 3 × 10-5M did not protect against nicotinic desensitization. Cyclo-SP(3-9), Ac-SP(3-9)-NH2, SP(3-9), and SP(3-6) had neither inhibitory nor facilitatory effects on secretion. Of the 20 SP analogues extended at the C terminus by one amino acid, there were only three that protected against nicotinic desensitization, whereas the majority inhibited nicotine-evoked catecholamine secretion. The present work indicates that for inhibition of nicotine-evoked secretion, both the C terminus and N terminus of SP are necessary. For the protection against nicotine-induced desensitization, the C terminus of SP is important. This suggests that the two mechanisms, inhibition of nicotine-evoked secretion and protection against nicotinic desensitization, are regulated independently.

Notes: Spring wheat (Triticum aestivum L. cv. Dragon) was exposed to elevated carbon dioxide (CO2), alone (1995) or in combination with two levels of increased ozone (O3) (1994) or increased irrigation (1996) during three successive growing seasons as part of the EU ESPACE-wheat programme and conducted in open-top chambers (OTCs) and ambient air (AA) plots at Östad, 50 km north-east of Göteborg, Sweden. Doubling the CO2 concentration had a positive effect on grain yield in all 3 years (+21, +7 and +11%, respectively), although only statistically significant in 1994. That year was characterised by a warm and dry summer in comparison with 1995 and 1996, in which the summers were more humid and typical for south-west Sweden. In 1994, the CO2-induced increase in grain yield was associated with an increase in the duration of the green leaf area, a positive effect on straw yield and on the number of ears per square metre and a negative effect (−13%) on grain protein concentration. Harvest index was unaffected by the elevated CO2 concentration. The only statistically significant effect of elevated CO2 in 1995 was a decrease in the grain protein concentration (−11% in both CO2 concentrations), and in 1996 an increase (+21%) in the straw yield. In 1996 the soil water potential was less negative in elevated CO2, which is likely to reflect a lower water consumption of these plants. Addition of extra O3 significantly affected the grain yield (−6 and −10%, respectively) and the 1 000-grain weight negatively (−3 and −6%). Statistically significant interactions between CO2 and O3 were obtained for the number of ears per unit area and for the 1 000-grain weight. The 1 000-grain weight was negatively affected by O3 in low CO2, but remained unaffected in the high CO2 treatment. There was a significant decrease (−6%) in the grain protein concentration induced by elevated irrigation. The chambers, compared with AA plots, had a positive effect on plant development and on grain yield in all 3 years.

Notes: Saplings of one clone of Norway spruce, Picea abies (L.) Karst, were planted in 120 l pots in 1991 and exposed to three levels of ozone, two levels of phosphorus and two levels of water supply in 42 open-top chambers (OTCs), during 1992–1996. The effects of pots and OTCs were also tested. Nutrient concentrations of the needles were not affected by ozone, while the low phosphorus supply (LP) and drought stress (D) treatments had significant effects on several mineral nutrients, e.g. phosphorus, calcium, magnesium, manganese, sulphur and boron. Ozone reduced the chlorophyll concentration in the 2- and 3-year-old needles in 1994 and 1995. The highest ozone concentration reduced the stem volumes (− 8%), as well as the stem lengths (− 5%), of the saplings in 1993 and 1994, after two and three years of exposure. After the fourth growing season this ozone-induced reduction in stem volume disappeared which might be caused by pot limitation. LP supply and D both caused large decreases in the stem volume and length. The needles from LP treatment had as high P concentration as 1.2–1.5 mg g−1, implying a need for increasing the critical value for phosphorus. The OTC enclosure stimulated the stem volume growth significantly compared to saplings growing in ambient plots. This was suggested to be attributed to the slightly higher temperature in the OTCs. The overall result is that ozone in southern Sweden is likely to have negative effects on Norway spruce trees, although much less than other environmental factors, e.g. water and phosphorus.

Notes: The stomatal response to blue light (BL) in wheat seedlings (Triticum aestivum L. cv. Starke II, Weibull) was enhanced by background red light (R). This enhancement was only slightly affected by the addition of background far-red light (FR). Under similar light treatments, the addition of FR induced a 43% transformation from the far-red-absorbing form towards the red-absorbing form of phytochrome from etiolated oat (Avena sativa L. cv. Sol II), immobilized on phenyl-sepharose. Furthermore, the enhancement of the stomatal BL-response by 15 min R was not reversed by a subsequent irradiation with 5 min FR. It is concluded that the red-light-enhancement of the stomatal blue-light-response in wheat seedlings does not involve a change in the photostationary state of phytochrome.

Notes: A red background illumination synergistically increased the sensitivity of the stomatal conductance response to low intensity blue light in wheat seedlings (Triticum aestivum L. cv. Starke II, Weibull). It also saturated the photosynthesis dependent mechanisms so that they did not respond to the low quantum fluence rates needed to activate the blue light mechanism. Thus dual beam experiments provide a suitable experimental approach to study the blue light mechanism for stomatal regulation in the intact leaf. Time course studies indicated that in short time experiments the enhancement effect of the red background light was primarily a result of the increase in conductance level rather than a direct effect of the red light. This was confirmed with experiments where the stomatal blue light response was enhanced due to partial stomatal opening in CO2 free air as well as due to circadian rhythm. During long term experiments the response to blue light gradually decreased. It could then, however, be restored by a simultaneous red background light.

Notes: The stomatal conductance response to low intensity blue light was studied in wheat seedlings (Triticum aestivum L. cv. Starke II, Weibull) under red background illumination. Reciprocity was shown to be valid for illumination times from 10 s up to about 2 min. The action spectrum, constructed from fluence rate response curves, showed a maximum peak at 445–450 nm, another peak at 470 nm, a slight shoulder at 420 nm and a plateau between 370–400 nm. The relationship with action spectra for other blue light responses is discussed. The blue light response of wheat stomata did not exhibit action dichroism (the direction of the electrical vector of polarized blue light did not influence the response of the guard cells).

Notes: Wheat seedlings (Truicum aestivum L. cv. Starke II, Weibull) grown in a solution of the herbicide SAN 9789 axe deficient in chlorophyll and carotenoids. Such seedlings were used in order to isolate a blue light response of stomata, not mediated by photosynthesis. When illuminated with blue light (430-505 nm) SAN-grown seedlings showed a considerable transpiration response, whereas red light (〉590 nm) gave no response whatsoever with the intensities used. The transpiration was measured with hygrometers in an open air-flow system. Furthermore, blue light had a superior effect, relative to red, in causing a transpiration response in untreated green seedlings. The transpiration level after two hours of illumination was higher in blue than in red light, although the blue light had its major effect immediately after the light was switched on. The difference between the effects of blue and red light was most pronounced at low light intensities. This, together with the high sensitivity of SAN-grown seedlings to low ntensity blue light, led to the conclusion that blue light is of special importance at low quantum fluxes. Because of the very low carotenoid content in the SAN-grown seedlings, the role of the carotenoids as photoreceptors for the blue light response of stomata was excluded.

Notes: Abstract (−)-Norepinephrine is the predominant neurotransmitter of the sympathetic innervation of the heart. Racemic norepinephrine was labelled with carbon-11 and injected i.v. into Cynomolgus monkeys. Five minutes after injection there was a more than tenfold higher radioactivity in the heart than in adjacent tissue. Pretreatment with the norepinephrine reuptake inhibitor desipramine reduced the uptake by more than 80%. The high specific uptake of racemic [11C]norepinephrine indicates that enatiomerically pure (−)-[11C]norepinephrine has promising potential for detailed mapping of the sympathetic innervation of the human myocardium.

Notes: Abstract.  [carbonyl-11C]Desmethyl-WAY-100635 (DWAY) is possibly a low-level metabolite appearing in plasma after intravenous administration of [carbonyl-11C]WAY-100635 to human subjects for positron emission tomographic (PET) imaging of brain 5-HT1A receptors. In this study we set out to assess the ability of DWAY to enter brain in vivo and to elucidate its possible interaction with 5-HT1A receptors. Desmethyl-WAY-100635 was labelled efficiently with carbon-11 (t 1/2 = 20.4 min) in high specific radioactivity by reaction of its descyclohexanecarbonyl analogue with [carbonyl-11C]cyclohexanecarbonyl chloride. The product was separated in high radiochemical purity by high-performance liquid chromatography (HPLC) and formulated for intravenous injection. Rats were injected intravenously with DWAY, sacrificed at known times and dissected to establish radioactivity content in brain tissues. At 60 min after injection, the ratios of radioactivity concentration in each brain region to that in cerebellum correlated with previous in vitro and in vivo measures of 5-HT1A receptor density. The highest ratio was about 22 in hippocampus. Radioactivity cleared rapidly from plasma; HPLC analysis revealed that DWAY represented 55% of the radioactivity in plasma at 5 min and 33% at 30 min. Only polar radioactive metabolites were detected. Subsequently, a cynomolgus monkey was injected intravenously with DWAY and examined by PET. Maximal whole brain uptake of radioactivity was 5.7% of the administered dose at 5 min after injection. The image acquired between 9 and 90 min showed high radioactivity uptake in brain regions rich in 5-HT1A receptors (e.g. frontal cortex and neocortex), moderate uptake in raphe nuclei and low uptake in cerebellum. A transient equilibrium was achieved in cortical regions at about 60 min, when the ratio of radioactivity concentration in frontal cortex to that in cerebellum reached 6. The corresponding ratio for raphe nuclei was about 3. Radioactive metabolites appeared rapidly in plasma, but these were all more polar than DWAY, which represented 52% of the radioactivity in plasma at 4 min and 20% at 55 min. In a second PET experiment, in which a cynomolgus monkey was pretreated with the selective 5-HT1A receptor antagonist, WAY-100635, at 25 min before DWAY injection, radioactivity in all brain regions was reduced to that in cerebellum. Autoradiography of post mortem human brain cryosections after incubation with DWAY successfully delineated 5-HT1A receptor distribution. Receptor-specific binding was eliminated in the presence of the selective 5-HT1A receptor agonist, 8-OH-DPAT [(±)-8-hydroxy-2-dipropylaminotetralin]. These findings show that: (a) intravenously administered DWAY is well able to penetrate brain in rat and monkey, (b) DWAY is a highly effective radioligand for brain 5-HT1A receptors in rat and monkey in vivo and for human brain in vitro, and (c) the metabolism and kinetics of DWAY appear favourable to successful biomathematical modelling of acquired PET data. Thus, DWAY warrants further evaluation as a radioligand for PET studies of 5-HT1A receptors in human brain.

Notes: Abstract NNC 12-0722 (1-[2-(bis(4-fluorophenyl)methoxy)ethyl]-4-methyl piperazine) is a new selective inhibitor of the dopamine transporter. [11C]NNC 12-0722 was prepared by N-methylation of the desmethyl compound with [11C]methyl iodide. The total radiochemical yield of [11C]NNC 12-0722 was 40%–50% with an overall synthesis time of 30–35 min. The radiochemical purity was higher than 99% and the specific radioactivity about 1500 Ci/mmol (55 GBq/μmol). Autoradiographic examination of [11C]NNC 12-0722 binding on whole hemisphere cryosections from human brain post mortem demonstrated specific binding in the caudate nucleus and putamen. In a positron emission tomographic examination of [11C]NNC 12-0722 in a cynomolgus monkey there was a rapid uptake of radioactivity in the brain. In the striatum, a region with a high density of dopamine transporters, the radioactivity was two times higher than in the cerebellum. These results indicate that [11C]NNC 12-0722 may be a useful radioligand for labelling of the dopamine transporter in man.