The chloroplast genome of the hexaploid Spartina maritima (Poaceae, Chloridoideae): Comparative analyses and molecular dating.

The history of many plant lineages is complicated by reticulate evolution with cases of hybridization often followed by genome duplication (allopolyploidy). In such a context, the inference of phylogenetic relationships and biogeographic scenarios based on molecular data is easier using haploid markers like chloroplast genome sequences. Hybridization and polyploidization occurred recurrently in the genus Spartina (Poaceae, Chloridoideae), as illustrated by the recent formation of the invasive allododecaploid S. anglica during the 19th century in Europe. Until now, only a few plastid markers were available to explore the history of this genus and their low variability limited the resolution of species relationships. We sequenced the complete chloroplast genome (plastome) of S. maritima, the native European parent of S. anglica, and compared it to the plastomes of other Poaceae. Our analysis revealed the presence of fast-evolving regions of potential taxonomic, phylogeographic and phylogenetic utility at various levels within the Poaceae family. Using secondary calibrations, we show that the tetraploid and hexaploid lineages of Spartina diverged 6-10 my ago, and that the two parents of the invasive allopolyploid S. anglica separated 2-4 my ago via long distance dispersal of the ancestor of S. maritima over the Atlantic Ocean. Finally, we discuss the meaning of divergence times between chloroplast genomes in the context of reticulate evolution.

Compartmentalized beta subunit distribution determines characteristics and ethanol sensitivity of somatic, dendritic, and terminal large-conductance calcium-activated potassium channels in the rat central nervous system.

Neurons are highly differentiated and polarized cells, whose various functions depend upon the compartmentalization of ion channels. The rat hypothalamic-neurohypophysial system (HNS), in which cell bodies and dendrites reside in the hypothalamus, physically separated from their nerve terminals in the neurohypophysis, provides a particularly powerful preparation in which to study the distribution and regional properties of ion channel proteins. Using electrophysiological and immunohistochemical techniques, we characterized the large-conductance calcium-activated potassium (BK) channel in each of the three primary compartments (soma, dendrite, and terminal) of HNS neurons. We found that dendritic BK channels, in common with somatic channels but in contrast to nerve terminal channels, are insensitive to iberiotoxin. Furthermore, analysis of dendritic BK channel gating kinetics indicates that they, like somatic channels, have fast activation kinetics, in contrast to the slow gating of terminal channels. Dendritic and somatic channels are also more sensitive to calcium and have a greater conductance than terminal channels. Finally, although terminal BK channels are highly potentiated by ethanol, somatic and dendritic channels are insensitive to the drug. The biophysical and pharmacological properties of somatic and dendritic versus nerve terminal channels are consistent with the characteristics of exogenously expressed alphabeta1 versus alphabeta4 channels, respectively. Therefore, one possible explanation for our findings is a selective distribution of auxiliary beta1 subunits to the somatic and dendritic compartments and beta4 to the terminal compartment. This hypothesis is supported immunohistochemically by the appearance of distinct punctate beta1 or beta4 channel clusters in the membrane of somatic and dendritic or nerve terminal compartments, respectively.

Differential effects of the adenosine A(1) receptor allosteric enhancer PD 81,723 on agonist binding to brain and adipocyte membranes.

The benzoylthiophene analog, PD 81,723, has been shown to allosterically enhance agonist binding and functional activation of the mammalian adenosine (ADO) A(1) receptor subtype by putatively maintaining the receptor in a high affinity state. The present studies were conducted to evaluate the ability of PD 81,723 to enhance the binding of [3H]cyclohexyladenosine ([3H]CHA) to A(1) receptors of neural (cerebral cortex) and non-neural (adipocyte) origin in three different species; rat, guinea pig and dog. PD 81, 723 (0.3-100 microM) produced a concentration-dependent enhancement of [3H]CHA binding to rat brain A(1) receptors. These effects were also species-dependent with larger enhancements (150-200% of control) observed in guinea pig and dog brain membranes as compared to the rat (120% of control). In contrast, PD 81,723 did not produce any enhancement of [3H]CHA binding to A(1) receptors in adipocyte membranes from any of the species examined. Additional binding studies were conducted using pharmacological manipulations that have previously been shown to enhance the allosteric effects of PD 81,723. In the presence of 1 mM GTP, the allosteric effects of PD 81,723 (15 microM) were increased in rat, guinea pig and dog brain membranes, however, in adipocyte membranes from each species, no significant alteration in agonist binding was observed. Similarly, the A(1) receptor selective antagonist 8-cyclopentyl-1, 3-dipropylxanthine (added to effectively reduce the intrinsic antagonist properties of PD 81,723) was found to enhance the allosteric effects of PD 81,723 (15 microM) in brain, but produce no alteration of agonist binding in adipocyte membranes from each species. Examination of the dissociation kinetics of [3H]CHA binding from rat brain and adipocyte membranes revealed that PD 81,723 (15 microM) differentially slowed agonist dissociation from brain, but not adipocyte, membranes. Taken together, the present data support the hypothesis that in tissues that are sensitive to PD 81,723, this benzyolthiophene functions to maintain the A(1) receptor in a high-affinity state and that the relative proportions of high-affinity A(1) receptors present in specific tissues may contribute, at least in part, to the apparent differential effects of PD 81,723 on agonist binding. The tissue specific modulation of A(1) receptor function by PD 81,723 also illustrates the possibility that the locus of allosteric modulation by PD 81,723 may be manifest via a specific, but indirect and tissue-dependent, interaction with the A(1) receptor.

Granulosin, a new chromone from Galipea granulosa.

A novel chromone, granulosin (1), has been isolated from the bark of Galipea granulosa. The extract of the bark, as well as granulosin (1), exhibited lethality in the brine shrimp test. The structure of granulosin (1) as 2-propyl-7,8-(methylenedioxy)chromone was established via spectroscopic analysis.

RP 73870, a gastrin/cholecystokinin-B receptor antagonist with potent anti-ulcer activity in the rat.

RP 73870, the racemic potassium salt of (([N-(methoxy-3-phenyl)-N-(N-methyl-N-phenyl-carbamoylmethyl)- carbamoylmethyl]-3-ureido)-3-phenyl)-2-ethylsulfonate-(RS) is a potent, reversible antagonist of both gastrin and cholecystokinin-B receptors in guinea pig and rat tissues. This compound is a potent inhibitor of pentagastrin-stimulated gastric acid secretion in the perfused rat stomach. RP 73870 also inhibits basal gastric acid secretion in the rat, although at doses higher than that required for inhibition of pentagastrin-stimulated gastric acid secretion. RP 73870 is a potent inhibitor of aspirin-induced gastric damage in the rat. In the prevention of aspirin-induced gastric damage, RP 73870, given p.o., was 10-fold less potent than when given i.v. RP 73870 was as potent as a H2 receptor antagonist or proton pump inhibitor in the prevention of cysteamine-induced duodenal ulcers in the rat. Relative to other gastrin/cholecystokinin-B antagonists, RP 73870 demonstrates greater affinity to gastrin binding sites, and possesses a unique spectrum of in vivo biological activities appropriate for an anti-ulcer indication.

Adenosine agonists reduce conditioned avoidance responding in the rat.

Because adenosine agonists may possess therapeutic potential as antipsychotic agents, we examined the activity of several prototypic agents in vivo in blocking conditioned avoidance responding (CAR) in the rat, a behavioral test predictive of antipsychotic efficacy in humans. Potency in blocking CAR is directly proportional to potency in alleviating schizophrenia. Hence, the adenosine A1-selective agonists [cyclopentyl adenosine (CPA) and (R)-phenylisopropyl adenosine (R-PIA)], A2-selective agonists [CV-1808 and (2-(p-(carboxyethyl)-phenethylamino)-5'-N-ethyl-carboxamido adenosine (CGS 21680)], and a nonselective agonist [5'-N-carboxamido adenosine (NECA)] were examined in this test. Block of CAR was first determined for standard antipsychotic agents [ED50 mg/kg, IP, and 95% confidence level (CL) in parentheses], such as haloperidol [0.23 (0.18, 0.39)], trifluoroperazine [(0.9 (0.7, 1.0)], thioridazine [12.5 (10.5, 15.3)], metoclopramide [7.8 (6.4, 9.2)], and chlorpromazine [4.9 (4.2, 5.9)]. The paradigm consisted of a light- and tone-signaled footshock that could be avoided via a discrete lever press. Affinity for A1 and A2 binding sites in brain tissue from Fischer 344 rats was ascertained to be similar to that seen in other rodent strains. Each adenosine agonist blocked CAR. NECA [ED50 value (95% CL) = 0.07 (0.004, 0.12) mg/kg, IP] was the most potent agent, followed by: R-PIA [0.34 (0.23, 0.44)]; CGS 21680 [1.1 (0.8, 2.0)]; CV-1808 [1.3 (1.0, 1.8)]; and CPA [1.5 (1.3, 1.7)]. Pretreatment with caffeine (25 mg/kg, IP, -10 min) blocked the inhibition of CAR produced by the adenosine agonists, suggesting the event is mediated via purinergic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

The gastrin/cholecystokinin-B receptor antagonist L-365,260 reduces basal acid secretion and prevents gastrointestinal damage induced by aspirin, ethanol and cysteamine in the rat.

L-365,260, a nonpeptide antagonist of gastrin/CCK-B receptors, was evaluated in receptor binding, antisecretory and gastrointestinal damage assays. L-365,260 binds potently and stereo-selectively to gastrin and CCK-B sites in guinea pig tissue. In contrast, L-365,260 binds to the isolated canine parietal cell gastrin receptor weakly, and without stereoselectivity. In the pylorus-ligated rat, low doses of L-365,260, given i.v., attenuated pentagastrin-stimulated acid secretion, whereas higher doses were required to inhibit both histamine-stimulated and basal acid secretion. In an aspirin-induced gastric damage model, L-365,260 was 2.4-fold less potent than the standard histamine H2 antagonist cimetidine in preventing gastric damage when given i.v., and was 8.3-fold less potent than cimetidine when given p.o. Moreover, the ED50 value for L-365,260, given i.v., in prevention of aspirin-induced gastric damage (11.5 mg/kg) agreed well with its ED50 value for inhibition of basal acid secretion (12.6 mg/kg). At doses as great as 100 mg/kg p.o., neither L-365,260 nor cimetidine had an effect on ethanol-induced gastric damage. L-365,260, although p.o. less bioavailable relative to cimetidine in the aspirin gastric damage model, was as potent as cimetidine in the prevention of cysteamine-induced duodenal ulcers in the rat. We conclude that the gastrin/CCK-B receptor antagonist L-365,260, at doses supramaximal for the inhibition of pentagastrin-stimulated secretory responses in vivo, inhibits gastrointestinal damage in models of peptic ulcer disease by an antisecretory mechanism of action.

Acidic fibroblast growth factor accelerates the healing of acetic-acid-induced gastric ulcers in rats.

Acidic fibroblast growth factor (aFGF) was evaluated for the healing of acetic-acid-induced gastric ulcers in rats. The effect of aFGF on angiogenesis in the gastric ulcer bed was determined by the carmine dye infusion method, while its effect on gastric acid secretion was assessed in chronic gastric fistula rats. Oral treatment with aFGF, in the presence of heparin, reduced (ED50 value = 30.2 micrograms/kg/day) the acetic-acid-induced gastric ulcer area, when assessed 1 week later. aFGF was about 1,333-fold more potent than famotidine for healing such ulcers. At a dose of 200 micrograms/kg/day, aFGF increased the carmine density 3-fold and correspondingly reduced (80%) the gastric ulcer area. Thus, the ulcer healing effect of this agent involves angiogenesis in the gastric ulcer bed. This effect of aFGF appears to be unrelated to an inhibition of gastric acid secretion, as it was ineffective in chronic gastric fistula rats. In summary, oral aFGF significantly accelerates the healing of experimental gastric ulcers in rats. It may be a potent and effective agent for the treatment of peptic ulcers in humans.

RG 12915: a potent 5-hydroxytryptamine-3 antagonist that is an orally effective inhibitor of cytotoxic drug-induced emesis in the ferret and dog.

RG 12915 [4-[N-(1-azabicyclo[2.2.2.]octan-3-(S)-yl)]2-chloro-cis 5a-(S)-9a-(S)-5a,6,7,8,9,9a-hexahydrobenzofurancarboxamide hydrochloride] is a potent and effective agent against cisplatin-induced emesis in the ferret after i.v. or p.o. administration. This agent (p.o.) is also highly protective against cisplatin-induced emesis in the dog, as well as cyclophosphamide/doxorubicin-induced emesis in the ferret. When administered either p.o. or i.v., RG 12915 has a lower ED50 value (0.004 mg/kg) than GR 38032F, BRL 43694 and metoclopramide for attenuating cisplatin-induced emetic episodes in the ferret. It also has a long duration of action against cisplatin-induced emesis in the ferret. In contrast to metoclopramide, RG 12915 lacks significant antidopaminergic activity both in vitro [( 3H]spiroperidol displacement), as well as in vivo (apomorphine-induced emesis). In radioligand binding assays, RG 12915 is a potent and selective displacer of binding of 5-hydroxytryptamine (5-HT)3 binding sites (IC50 value = 0.16 nM), whereas failing to displace binding of ligands for the alpha-1, alpha-2 and beta adrenergic, 5-HT1 or 5-HT2 or cholinergic-muscarinic sites with IC50 values less than 1 microM. At a p.o. dose (1 mg/kg) in which RG 12915 is highly protective against cisplatin-induced emesis in the dog, RG 12915 has no significant gastroprokinetic activity in the same species. In summary, RG 12915 is a potent and p.o. effective agent against cytotoxic drug-induced emesis in animal models. The antiemetic potency of RG 12915 against cisplatin is unrelated to antidopaminergic or gastroprokinetic activity, but may be related to its affinity for 5-HT3 binding sites.

Isolation of the cembranolide diterpenes dihydrosinularin and 11-epi-sinulariolide from the marine mollusk Planaxis sulcatus.

Marine mollusks have been identified as a rich source of novel compounds. The diversity of the chemical nature of these compounds can be partially attributed to the dietary sources inasmuch as mollusks are known to concentrate selectively compounds present in their diet. Although cembranolide diterpenses have been isolated in ever-growing numbers from a variety of marine as well as terrestrial sources, there is only one report about their presence in a marine mollusk. In this communication, we report the isolation of dihydrosinularin and 11-epi-sinulariolide from the mollusk Planaxis sulcatus Born. Dihydrosinularin and 11-epi-sinulariolide acetate have been isolated previously from soft corals which, together with gorgonians, are the richest sources of marine cembranoids. It should be pointed out that this is the first report on the occurrence of the parent 11-epi-sinulariolide in a marine invertebrate. It is expected these diterpenes are of dietary origin although the possibility of biotransformation of a precusor by the mollusk cannot be ruled out at this time. Both dihydrosinularin and 11-epi-sinulariolide have been reported to have marginal antineoplastic activity against P-388 lymphocytic leukemia.

Selectivity of (+)-4-propyl-9-hydroxynaphthoxazine [(+)-PHNO] for dopamine receptors in vitro and in vivo.

The intrinsic activity of the potent dopamine (DA) agonist 4-propyl-9-hydroxynaphthoxazine [(+)-PHNO] was examined in receptor binding assays for the following receptors: DA, alpha-1 and alpha-2 adrenergic, serotonin-1 and -2, neuroleptic, beta adrenergic, anxiolytic, adenosine A-1, gamma-aminobutyric acid, muscarinic and opiate. (+)-PHNO exhibited strong to moderate potencies [IC50 (nanomolars) in parentheses] in binding to DA (24), "neuroleptic" (67), alpha-2 adrenergic (77) and serotonin-1 (277) sites. The pharmacological activity of the naphthoxazine both in vivo and in vitro was contrasted with the known DA agonists apomorphine, pergolide, lisuride and 6-ethyl-9-oxaergoline in tests of DA, alpha-2 adrenergic and serotonergic function. Each compound was examined in vitro in receptor binding assays for interactions with DA, alpha-2 adrenergic, serotonin-1 and serotonin-2 receptors and for alpha-2 adrenergic activity in inhibiting field-stimulated contractions of the vas deferens of the rat. In vivo, alpha-2 adrenergic activity was assayed via measurement of mydriasis after i.v. injections in the rat, whereas serotonin activity was assayed by measuring drug-induced inhibition of 5-hydroxytryptophan accumulation, and DA activity was assessed by quantifying stereotyped behavior after both i.p. and i.v. injections. Selectivity ratios for the DA receptor were derived from effective dose values determined in these tests and demonstrated that only apomorphine was more selective as a DA agonist than (+)-PHNO in vivo. (+)-PHNO was the least active agent at the alpha-2 receptors in the vas deferens and with serotonergic mechanisms in vivo to reduce 5-hydroxytryptophan accumulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Congestive heart failure due to giant cutaneous cavernous hemangioma.

A female infant is presented with isolated giant cutaneous cavernous hemangioma with secondary severe congestive heart failure. Studies to identify other major arteriovenous malformations were negative. An attempt to treat the patient with a corticosteroid was not successful in reducing the size of the hemangioma. She required an aggressive anticongestive medical regimen for 2 years. Though not previously described, high output congestive heart failure can occur secondary to isolated cutaneous hemangioma. Aggressive medical management may alleviate the need for the increased risk of surgical or other therapeutic approaches in this often self-limited condition.

Gas-liquid chromatographic determination of beta-asarone in wines and flavors.

Wine samples containing beta-asarone (cis-2,4,5-trimethoxy-l-propenylbenzene) are distilled; beta-asarone is extracted by hexane and then quantitatively determined by gas-liquid chromatography (GLC), using ethyl palmitate as the internal standard. The GLC procedure is rapid and yields precise and accurate results. Mass spectrometry confirmed the identity of the GLC peak as beta-asarone. The ultraviolet spectra of beta-asarone and its isomer were also determined.