Cannabinoid 1 receptors modulate intestinal sensory and motor function in rat.

BACKGROUND: Cannabinoid receptors are involved in visceral pain perception and control of intestinal motility in vivo. The underlying mechanisms are not well characterized. We aimed to determine whether the cannabinoid-1 (CB(1)) receptor modulates intestinal afferent nerve discharge and the peristaltic reflex. METHODS: Rats were anesthetized and intestinal segments were removed. Afferent nerve discharge from a mesenteric nerve was investigated in vitro in the presence of the CB(1) antagonist SR 141716A or the CB(1) agonist WIN 55212-2. The myenteric peristaltic reflex was induced by electrical field stimulation and influence of SR 141716A or WIN 55212-2 was recorded. KEY RESULTS: Afferent nerve discharge to the algesic mediator bradykinin was reduced to 11 +/- 5.1 imp s(-1) following pretreatment with SR 141716A and unchanged after WIN 55212-2 compared to 63 +/- 15.4 imp s(-1) in controls. At maximum distension pressure (80 cmH(2)O) during ramp distension, 92 +/- 12.4 imp s(-1) were reached following SR 141716A compared to 260 +/- 13.2 in vehicle controls and 227 +/- 15.4 in WIN 55212-2 pretreated animals. In contrast, afferent discharge to 5-HT (500 micromol L(-1)) was increased to 75 +/- 24.6 imp s(-1) following WIN 55212-2 compared to 18 +/- 5.9 imp s(-1) in controls, whereas SR 141716A had no effect. Ascending neuronal contractions were dose-dependently attenuated in the presence of SR 141716A and latency of these contractions was reduced. WIN 55212-2 had opposite effects that were abolished by SR 141716A. CONCLUSIONS & INFERENCES: Activation of the CB(1) receptor differentially alters afferent intestinal nerve sensitivity to bradykinin, 5-HT, and noxious mechanical distension, while it strengthens ascending neuronal contractions. Further studies are needed to determine the physiological relevance of these observations.

Interactions of two cytotoxic organotin(IV) compounds with calf thymus DNA.

The reactions with DNA of two antitumor active organotin(IV) compounds, the dimer of bis[(di-n-butyl 3,6-dioxaheptanoato)tin] (C(52)H(108)Sn(4)O(1) x 2H(2)O), compound 1, and tri-n-butyltin 3,6,9-trioxodecanoate (C(19)H(40)SnO(5) x 1/2H(2)O), compound 2, were analysed by circular dichroism, DNA melting experiments and gel mobility shift assays. It is found that both complexes modify only slightly the B-type circular dichroism spectroscopy (CD) spectrum of calf thymus DNA. On the other hand, both complexes were found to affect significantly the parameters of the thermally induced helix-to-coil transition. Addition of 1 or 2 to calf thymus DNA samples does not favor DNA renaturation after melting ruling out formation of interstrand crosslinks. Moreover, the effects of both compounds on plasmid DNA gel mobility were investigated. From the analysis of the present results it is inferred that both organotin(IV) compounds do interact with DNA, probably at the level of the phosphate groups.

Functional organization of the dorsal cochlear nucleus of the horseshoe bat (Rhinolophus rouxi) studied by GABA and glycine immunocytochemistry and electron microscopy.

Unique among mammals, the dorsal cochlear nucleus (DCN) of horseshoe bats consists of two functionally and anatomically distinct subdivisions: a laminated ventral portion that processes the frequency range below the constant frequency (CF) component of the echolocation signal and a nonlaminated dorsal portion that is specialized for processing the CF-signal range (76 kHz and higher). Using conventional transmission electron microscopy and postembedding immunocytochemistry for the inhibitory neurotransmitters GABA and glycine on semithin-alternating sections, we present further evidence that the ventral laminated subdivision of DCN conserves the main elements of microcircuitry and GABA/glycine labeling patterns typical for the mammalian DCN: (i) the main cell types and synaptic inventory of the granule cell/cartwheel cell system of the superficial layers are present as well as (ii) the tuberculoventral cell system of the deep layers. The nonlaminated dorsal subdivision lacks the granule cell/cartwheel cell system and is composed of a mixture of fusiform projection neurons with tuberculoventral cell analogues. Thus the inhibitory tuberculoventral system known to play an important role in temporal and spectral processing in VCN is conserved throughout the DCN of horseshoe bats, whereas functional components of cerebellar-like circuits are reduced in a specialized region that processes the dominant biosonar component.

Cellular and subcellular distribution of AMPA-type glutamate receptor subunits and metabotropic glutamate receptor 1alpha in the cochlear nucleus of the horseshoe bat (Rhinolophus rouxi).

Ionotropic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) selective glutamate receptors (GluRs) are the main mediators of fast excitatory neurotransmission and composed of a variable combination of four different subunits (GluR1-4). The metabotropic glutamate receptor 1alpha (mGluR1alpha) is involved in plastic synaptic events. Since horseshoe bats strongly depend on temporal cues for acoustic imaging by echolocation and exhibit prominent species specific specializations of the cochlear nucleus (CN), the subunit distribution of AMPA selective GluRs and the distribution of mGluR1alpha was studied at the light and electron microscopic level with preembedding immunocytochemistry. Immunoreactivity to GluR1 was low throughout the CN. All types of projection neurons of the ventral CN expressed distinct GluR2/3 and GluR4 immunoreactivity with GluR4-labeling especially prominent in multipolar and octopus cell-like neurons of the posteroventral CN. The AMPA and metabotropic receptor inventory of the laminated ventral subdivision of the dorsal CN (DCNv) agreed with that reported in other mammals, whereas the specialized dorsal non-laminated subdivision of DCN (DCNd) lacked the prominent labeling for GluR2/3 and mGluR1alpha that characterizes cartwheel cells of DCNv. Distinct GluR2/3 and GluR4 immunoreactivity combined with low expression of mGluR1alpha immunoreactivity was characteristic for fusiform cells of DCNv and DCNd. Tuberculoventral cells of both the deep DCNv and the DCNd exhibited light to moderate GluR2/3 and GluR4 immunoreactivity. The staining patterns in DCNd thus indicate a loss of cerebellar-like microcircuits and a conservation of frequency specific circuitry of the deep and fusiform cell layers of the mammalian DCN.

Complexation of triorganotin derivatives of [18]crown-6- and [15]crown-5-(benzo-4-carboxylate) with alkali thiocyanates.

Investigations of the simultaneous complexation of tri-n-butyltin and triphenyltin derivatives of [18]crown-6- or [15]crown-5-(benzo-4-carboxylate) by the anion and cation from NaSCN or KSCN are reported. The crystal structure of [Na+ is included in [15]crown-5-C6H3-4-COOSn(C6H5)3NCS]-], 4 NaSCN, displays an unusual zwitterionic nature with one intramolecular charge separation characterized by an Na-Sn distance of 9.29(1) A, and several intermolecular charge separations, the shortest being 5.48(1) A. Similar distances (9.70(2), 9.28(2), intramolecular; 5.40(2) and 5.41(2) A, shortest intermolecular) are observed in the more complicated structure of the corresponding [18]crown-6-(benzo-4-carboxylate) derivative, 3 NaSCN, with two independent molecules in the asymmetric unit. For the tri-n-butyltin analogues 1 and 2, complex equilibria were observed in acetone and unraveled by variable temperature 13C, 117Sn. and 23Na NMR studies. Their complexes with KSCN and NaSCN undergo decomposition in acetone solution, as evidenced by the transformation of [K+ is included in [18]crown-6-[C6H3-4-COOSn(nBu)3NCS]-], into tri-n-butyltin isothiocyanate and a novel dimeric potassium [18]crown-6-(benzo-4-carboxylate), the structure of which was elucidated by X-ray diffraction analysis.

Violene/cyanine hybrids as electrochromics part 2: tetrakis(4-dimethylaminophenyl)ethene and its derivatives

The general structure of violene/cyanine hybrids (see below) is exemplified by tetrakis(4-dimethylaminophenyl)ethene 1(RED) its vinylogue 2(RED) and its diazavinylogue 3(RED). As judged from their cyclic voltammograms and spectroelectrograms, oxidation occurs perfectly reversible by loss of two electrons creating closed shell systems 1-3(OX)+2 with strong bathochromic shifts (Michlers hydrol blue moieties). ESR spectra indicate only minor amounts of radical cations. At much higher potentials by another reversible loss of two electrons (-->1-3(OX)+4) the long wavelengths absorptions are replaced by shorter ones. In system 4, containing two 4-dimethylaminophenyl units only, the violene character is better preserved since oxidation occurs stepwise by single electron transfer up to 4(OX)+4. These results are backed by theoretical calculations for 1-4, demonstrating the strong geometrical differences between the various oxidation levels. Besides, new types of cyclic structures for 1-4(OX)+4 are indicated by these calculations: For systems 1-3 cyclic structures for tetracations have been found to be more stable by 3-20 kcalmol(-1) than acyclic structures, whereas for system 4 the acyclic structure is more stable by about 22 kcalmol(-1). The redox behavior of systems 1-4 is of general importance for electrochromic systems.

Synthesis, Characterization and In Vitro Antitumour Activity of Di-n-Butyl, Tri-n-Butyl and Triphenyltin 3,6-Dioxaheptanoates and 3,6,9-Trioxadecanoates.

A series of di- and triorganotin 3,6-dioxaheptanoates and 3,6,9-trioxadecanoates were synthesized and characterized by (1)H, (13) and (117)Sn NMR, electrospray mass and (119m)Sn Mössbauer spectroscopy, as well as elemental analysis. Their in vitro antitumour activity against seven tumoural cell lines of human origin, two breast cancers (MCF-7, EVSA-T), a colon carcinoma (WiDr), an ovarian cancer (IGROV), a melanoma (M 19 MEL), a renal cancer (A 498) and a non small cell lung cancer (H 226), is reported. They are characterized by similar inhibition doses ID(50) as the analogous di- and triorganotin derivatives of 4-carboxybenzo-15-crown-5 and -18-crown-6 and in some cases by much lower ID(50) values than clinically used reference compounds such as doxorubicine and methotrexate.

The distribution of GABA and glycine immunostaining in the cochlear nucleus of the mustached bat (Pteronotus parnellii).

The distribution of neuronal elements immunoreactive for gamma-aminobutyric acid (GABA) and glycine in the cochlear nucleus of the mustached bat Pteronotus parnellii has been studied by means of the postembedding technique on serial semithin sections. Our goal has been to identify similarities and differences in the organization of putatively inhibitory circuits between a highly specialized echolocating bat and previously studied non-echolocating mammals. The results reveal a basically conserved pattern of putatively GABAergic and glycinergic elements in the bat cochlear nucleus, and subtle but distinct modifications in certain inhibitory circuits. As in other mammals, immunoreactive cells possibly representing local interneurons are most abundant in the dorsal cochlear nucleus. These include single-GABA-immunoreactive cells and double-labeled cells in the superficial layers and single-glycine-labeled cells in the deep layers. Coincident with the phylogenetic trend toward a reduced lamination of the dorsal cochlear nucleus in bats, there is a clear reduction in the numbers of local interneurons of the superficial layer. In contrast, the tuberculoventral system of the deep layer appears hypertrophied. As in other mammals, the ventral cochlear nucleus contains a few large single-glycine-immunoreactive cells and scattered double-labeled cells. Immunoreactive puncta are abundant throughout the cochlear nucleus complex with no trends indicating a differential strength of inhibitory inputs to regions representing the various harmonics of the echolocating signal.

Serum ribonuclease activity in the diagnosis of pancreatic disease.

The present study evaluated serum ribonuclease activity (SRA) in patients with inflammatory and neoplastic pancreatic diseases. RNase determination was carried out using t-RNA (T) from E. coli MRE 600 at pH 7.4 and polycytidylic acid (poly-C) (P) at pH 6.6 as RNA substrates with RNase A from bovine pancreas as reference enzyme. Healthy volunteers had a SRA of T: 160 +/- 12 and P: 482 +/- 24 ngeq/mL (mean +/- SEM (n]. In patients with acute interstitial pancreatitis (AIP), SRA was similar to healthy controls (T: 166 +/- 14; P: 474 +/- 30 ngeq/mL). Patients with acute necrotizing pancreatitis (ANP) had increased SRA (T: 278 +/- 49; P: 791 +/- 145 ngeq/mL, p less than 0.01, compared to controls). SRA values were also increased in patients with chronic pancreatitis (CP) with T: 224 +/- 15 ngeq/mL (p less than 0.01) and in patients with pancreatic carcinoma (PCA) with T: 331 +/- 35 (p less than 0.001 vs controls, p less than 0.01 vs CP). Increased SRA was detected in patients with renal insufficiency (T: 2576 +/- 195 ngeq/mL, p less than 0.001). Diagnostic discrimination between AIP and ANP was achieved in 69% using T-SRA (sensitivity 31%, specificity 88%), and in 78% using P-SRA (sensitivity 54%, specificity 92%). Discrimination between CP and pancreatic carcinoma was possible in 68% (sensitivity 67%, specificity 71%). The diagnostic value of serum RNase is limited because of its low sensitivity, but increased T-SRA above a cutoff of 250 ngeq/mL and increased P-SRA above a cutoff of 620 ngeq/mL are specific for detecting pancreatic necrosis in the absence of renal impairment. The kidney is a major site for SRA clearance.

Pronounced cholinergic but only moderate purinergic effects in isolated atrial and ventricular heart muscle from cats.

1. The effects of cholinergic and purinergic stimulation on action potential, force of contraction and 86Rb efflux were investigated in cat atrial and/or ventricular heart muscle. 2. Acetylcholine and carbachol exerted a concentration-dependent negative inotropic effect in cat atrial heart muscle. Carbachol 10 mumol l-1 completely abolished the force of contraction and increased the rate constant of 86Rb efflux 2-3 fold, whereas the action potential duration was shortened to about 1/10 of its length under control conditions. 3. The effects of acetylcholine and carbachol in cat atrial heart muscle were mimicked, qualitatively, by adenosine and its analogues 5'-(N-ethyl)-carboxamido-adenosine (NECA) and (-)-N6-(R-phenyl-isopropyl)-adenosine (R-PIA). Maximal purinergic effects, however, amounted to about 15-50% in comparison to those of cholinergic stimulation. 4. In cat ventricular heart muscle, cholinergic or purinergic stimulation had no significant effects on the force of contraction in the absence of a cyclic AMP-dependent positive inotropic effect. Carbachol antagonized the positive inotropic effect elicited by either 3-isobutyl-1-methylxanthine, isoprenaline or cyclic 8-(4-chlorphenylthio)adenosine-3':5'-monophosphate; NECA and R-PIA were less effective. The inhibition by carbachol of the effects of isoprenaline was not related to a change in the rate constant of 86Rb efflux. 5. It is concluded that the effects of cholinoceptor and purinoceptor agonists in the cat heart involve a change in the potassium conductance in the atrium, whereas the effects in the ventricle may be related to changes of intracellular cyclic AMP levels. It seems reasonable to assume that, in comparison to cholinergic stimulation, a low density of purinoceptors in the cat heart is responsible for the relatively weak effects of adenosine agonists in this species.