RESUMO
BACKGROUND AND PURPOSE: Spinal N-methyl-D-aspartate (NMDA) receptor/cyclooxygenase (COX) and nitric oxide synthase (NOS) pathways play a major role in nociceptive processing, and influencing them simultaneously may induce synergistic analgesia. This study determined the spinal antinociceptive interactions between ketamine (NMDA receptor channel blocker), ketoprofen (COX inhibitor) and L-NAME (NOS inhibitor) combinations. EXPERIMENTAL APPROACH: Using an in vitro neonatal rat spinal cord preparation, two A-fibre-mediated reflexes, the monosynaptic reflex (MSR) and the low-intensity excitatory postsynaptic potential (epsp), and one C-fibre-mediated reflex, the high-intensity epsp, were evoked electrically. The effect of drugs and drug combinations on these reflexes was assessed and the type of interaction determined by isobolographic analysis. KEY RESULTS: Infusion of ketamine alone decreased all three reflexes. That of ketoprofen decreased both the low and the high-intensity epsp only. Infusion of L-NAME alone produced no significant effects. Co-infusion of fixed ratios of IC(40) fractions of both (ketamine+ketoprofen) and (ketamine+L-NAME) were synergistic for depressing the low and the high-intensity epsps. The interaction was sub-additive for both combinations on the MSR. The only significant effect for the (ketoprofen+L-NAME) combination was synergism on the high-intensity epsp. CONCLUSIONS AND IMPLICATIONS: All three combinations synergistically depressed nociceptive spinal transmission, and both ketamine and ketoprofen and ketamine and L-NAME combinations did so with potentially decreased motor side effects. If such combination profiles also occur in vivo, the present findings raise the possibility of ultimate therapeutic exploitation of increased analgesia with fewer side effects.
Assuntos
Ketamina/farmacologia , Cetoprofeno/farmacologia , NG-Nitroarginina Metil Éster/farmacologia , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Medula Espinal/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Inibidores de Ciclo-Oxigenase/efeitos adversos , Inibidores de Ciclo-Oxigenase/farmacologia , Sinergismo Farmacológico , Estimulação Elétrica , Eletrofisiologia , Inibidores Enzimáticos/efeitos adversos , Inibidores Enzimáticos/farmacologia , Potenciais Evocados , Antagonistas de Aminoácidos Excitatórios/efeitos adversos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Técnicas In Vitro , Ketamina/efeitos adversos , Cetoprofeno/efeitos adversos , NG-Nitroarginina Metil Éster/efeitos adversos , Ratos , Ratos Sprague-Dawley , Medula Espinal/metabolismoAssuntos
Carbono/metabolismo , Árvores , Atmosfera , Dióxido de Carbono/metabolismo , Modelos Biológicos , América do Sul , Tempo , Clima Tropical , MadeiraRESUMO
Over 200 beetle- and food-produced volatiles were collected from cultures of the saw-toothed grain beetleOryzaephilus surinamensis (L.) on oats. It proved possible to develop the electroantennogram recording technique for these beetles, despite their small size, allowing volatiles causing antennal responses to be identified by coupled GC-EAG and subsequent GCMS techniques. Three beetle-produced macrolide lactones were identified as (Z,Z)-3,6-dodecadien-11-olide, (Z,Z)-3,6-dodecadienolide, and (Z,Z)-5,8-tetradecadien-13-olide in an average ratio of 4.4â¶1â¶2. These have been reported as components of the aggregation pheromone from a different population of this species, although the ratio of the components produced was different. Three food volatiles with EAG activity were also identified: 1-octen-3-ol, 3-octanone, and nonanal. A mixture of the six identified volatiles produced similar levels of attraction, in a behavioral assay, to the entire mixture of collected volatiles.
RESUMO
The antennal and behavioral responses of the saw-toothed grain beetle,Oryzaephilus surinamensis, to the three components of its male-produced aggregation pheromone were investigated. EAG recordings showed no differences between the responses of the two sexes to the synthetic pheromone components. In contrast, laboratory behavioral assays demonstrated marked differences between the sexes. More females than males were consistently attracted to mixtures of the synthetic components, and this bias appeared to be caused by one component in the blend. Altering the blend ratio resulted in changes in the ratio of the sexes attracted. Thus, if, as suggested by preliminary work, males vary the blend produced, this should alter the relative response of the sexes to the aggregation pheromone.
RESUMO
Vacuum distillation of heat-treated carobs gave an aqueous, colorless, sweet-smelling distillate which was tested over a wide range of concentrations and found to be highly attractive to adultOryzaephilus surinamensis (L.). The materials responsible for the aroma were isolated from the distillate by saturating with sodium chloride and extracting into diethyl ether as separate acidic, neutral, and basic fractions. The extraction efficiency was checked by recombining portions of the three fractions and replacing the diethyl ether with water to give a "reconstituted distillate;" this was almost as attractive as the original distillate. Bioassay of aqueous solutions of the three separate fractions showed that the acidic was attractive, while the neutral and basic had little effect. The five major components of the acidic fraction were found to be acetic, isobutyric,n-butyric, 2-methylbutyric, and hexanoic (caproic) acids. Bioassay of these in aqueous solution, both separately and combined, showed that hexanoic acid was the most attractive and may be responsible for both the longer-lasting attractive effect of the carob distillate and for the effectiveness of carobs themselves used in bait bags to detect stored product insects.
RESUMO
A laboratory method has been devised for testing the attractancy of vapors to adultOryzaephilus surinamensis (L.). Of four solvent extracts prepared from pods of the carob tree [Ceratonia siliqua (L.)], all attractedO. surinamensis, but the least polar extract was the most active. Subdivision of extracts yielded a series of fractions, the most attractive of which contained a mixture of triglycerides with three or more double bonds per molecule. Twelve authentic triglycerides, either synthesized or purchased, elicited responses ranging from high to very low attractancy in a way which appeared to be related to the number, position, and geometrical shape of the double bonds in the molecules. By studying the response of the insects to five glyceride acids, three aldehydes, and three volatile fatty acids, it has been shown that it may be possible to explain the attractancy attributed to the triglycerides, which are involatile, in terms of the response to their volatile breakdown products.