Association of terpinolene and diclofenac presents antinociceptive and anti-inflammatory synergistic effects in a model of chronic inflammation.

Pharmacological treatment of inflammatory pain is usually done by administration of non-steroidal anti-inflammatory drugs (NSAIDs). These drugs present high efficacy, although side effects are common, especially gastrointestinal lesions. One of the pharmacological strategies to minimize such effects is the combination of drugs and natural products with synergistic analgesic effect. The monoterpene terpinolene (TPL) is a chemical constituent of essential oils present in many plant species, which have pharmacological activities, such as analgesic and anti-inflammatory. The association of ineffective doses of TPL and diclofenac (DCF) (3.125 and 1.25 mg/kg po, respectively) presented antinociceptive and anti-inflammatory effects in the acute (0, 1, 2, 3, 4, 5 and 6 h, after treatment) and chronic (10 days) inflammatory hyperalgesia induced by Freund's complete adjuvant (CFA) in the right hind paw of female Wistar rats (170-230 g, n=6-8). The mechanical hyperalgesia was assessed by the Randall Selitto paw pressure test, which determines the paw withdrawal thresholds. The development of edema was quantified by measuring the volume of the hind paw by plethismography. The TPL/DCF association reduced neutrophils, macrophages and lymphocytes in the histological analysis of the paw, following a standard staining protocol with hematoxylin and eosin and the counts were performed with the aid of optical microscopy after chronic oral administration of these drugs. Moreover, the TPL/DCF association did not induce macroscopic gastric lesions. A possible mechanism of action of the analgesic effect is the involvement of 5-HT2A serotonin receptors, because ketanserin completely reversed the antinociceptive effect of the TPL/DCF association. These results suggest that the TPL/DCF association had a synergistic anti-inflammatory and analgesic effect without causing apparent gastric injury, and that the serotonergic system may be involved in the antinociceptive effect of this association.

Association of terpinolene and diclofenac presents antinociceptive and anti-inflammatory synergistic effects in a model of chronic inflammation

Pharmacological treatment of inflammatory pain is usually done by administration of non-steroidal anti-inflammatory drugs (NSAIDs). These drugs present high efficacy, although side effects are common, especially gastrointestinal lesions. One of the pharmacological strategies to minimize such effects is the combination of drugs and natural products with synergistic analgesic effect. The monoterpene terpinolene (TPL) is a chemical constituent of essential oils present in many plant species, which have pharmacological activities, such as analgesic and anti-inflammatory. The association of ineffective doses of TPL and diclofenac (DCF) (3.125 and 1.25 mg/kg po, respectively) presented antinociceptive and anti-inflammatory effects in the acute (0, 1, 2, 3, 4, 5 and 6 h, after treatment) and chronic (10 days) inflammatory hyperalgesia induced by Freund's complete adjuvant (CFA) in the right hind paw of female Wistar rats (170-230 g, n=6-8). The mechanical hyperalgesia was assessed by the Randall Selitto paw pressure test, which determines the paw withdrawal thresholds. The development of edema was quantified by measuring the volume of the hind paw by plethismography. The TPL/DCF association reduced neutrophils, macrophages and lymphocytes in the histological analysis of the paw, following a standard staining protocol with hematoxylin and eosin and the counts were performed with the aid of optical microscopy after chronic oral administration of these drugs. Moreover, the TPL/DCF association did not induce macroscopic gastric lesions. A possible mechanism of action of the analgesic effect is the involvement of 5-HT2A serotonin receptors, because ketanserin completely reversed the antinociceptive effect of the TPL/DCF association. These results suggest that the TPL/DCF association had a synergistic anti-inflammatory and analgesic effect without causing apparent gastric injury, and that the serotonergic system may be involved in the antinociceptive effect of this association.

Involvement of AOX and UCP pathways in the post-harvest ripening of papaya fruits.

Enhanced respiration during ripening in climacteric fruits is sometimes associated with an uncoupling between the ATP synthesis and the mitochondrial electron transport chain. While the participation of two energy-dissipating systems, one of which is mediated by the alternative oxidase (AOX) and the other mediated by the uncoupling protein (UCP), has been linked to fruit ripening, the relation between the activation of both mitochondrial uncoupling systems with the transient increase of ethylene synthesis (ethylene peak) remains unclear. To elucidate this question, ethylene emission and the two uncoupling (AOX and UCP) pathways were monitored in harvested papaya fruit during the ripening, from green to fully yellow skin. The results confirmed the typical climacteric behavior for papaya fruit: an initial increase in endogenous ethylene emission which reaches a maximum (peak) in the intermediate ripening stage, before finally declining to a basal level in ripe fruit. Respiration of intact fruit also increased and achieved higher levels at the end of ripening. On the other hand, in purified mitochondria extracted from fruit pulp the total respiration and respiratory control decrease while an increase in the participation of AOX and UCP pathways was markedly evident during papaya ripening. There was an increase in the AOX capacity during the transition from green fruit to the intermediate stage that accompanied the transient ethylene peak, while the O2 consumption triggered by UCP activation increased by 80% from the beginning to end stage of fruit ripening. Expression analyses of AOX (AOX1 and 2) and UCP (UCP1-5) genes revealed that the increases in the AOX and UCP capacities were linked to a higher expression of AOX1 and UCP (mainly UCP1) genes, respectively. In silico promoter analyses of both genes showed the presence of ethylene-responsive cis-elements in UCP1 and UCP2 genes. Overall, the data suggest a differential activation of AOX and UCP pathways in regulation related to the ethylene peak and induction of specific genes such as AOX1 and UCP1.

Blockade by agmatine of catecholamine release from chromaffin cells is unrelated to imidazoline receptors.

The blockade of exocytosis induced by the putative endogenous ligand for imidazoline receptors, agmatine, was studied by using on-line measurement of catecholamine release in bovine adrenal medullary chromaffin cells. Agmatine inhibited the acetylcholine-evoked release of catecholamines in a concentration-dependent manner (IC(50)=366 microM); the K(+)-evoked release of catecholamines was unaffected. Clonidine (100 microM) and moxonidine (100 microM) also inhibited by 75% and 50%, respectively, the acetylcholine-evoked response. In cells voltage-clamped at -80 mV, the intermittent application of acetylcholine pulses elicited whole-cell inward currents (I(ACh)) that were blocked 63% by 1 mM agmatine. The onset of blockade was very fast (tau(on) = 31 ms); the recovery of the current after washout of agmatine also occurred very rapidly (tau(off = 39 ms). Efaroxan (10 microM) did not affect the inhibition of I(ACh) elicited by 1 mM agmatine. I(ACh) was blocked 90% by 100 microM clonidine and 50% by 100 microM moxonidine. The concentration-response curve for acetylcholine to elicit inward currents was shifted to the right in a non-parallel manner by 300 microM agmatine. The blockade of I(ACh) caused by agmatine (100 microM) was similar at various holding potentials, around 50%. When intracellularly applied, agmatine did not block I(ACh). At 1 mM, agmatine blocked I(Na) by 23%, I(Ba) by 14%, I(K(Ca)) by 16%, and I(K(VD)) by 18%. In conclusion, agmatine blocks exocytosis in chromaffin cells by blocking nicotinic acetylcholine receptor currents. In contrast to previous views, these effects seem to be unrelated to imidazoline receptors.

A cross-sectional serodiagnostic survey of canine leishmaniasis due to Leishmania chagasi.

Jequie, a community of about 144,500 inhabitants located in the State of Bahia, Brazil, is endemic for both visceral and cutaneous leishmaniases. In the present epidemiologic study, the urban and inhabited periurban areas of the town were divided into 140 clusters of 0.25 km2 each. The seroprevalence of canine Leishmania antibodies was investigated using an enzyme-linked immunosorbent assay as a screening test since its sensitivity was significantly higher than that of an indirect immunofluorescence assay. A total of 1,681 dogs was surveyed in 34 randomly sampled clusters. The overall prevalence of Leishmania antibodies in the dog population was 23.5%, with intracluster prevalences ranging from 0% to 67%. There was no correlation of these seroprevalences with the intracluster densities of canine populations, or with the distances from individual clusters to the town center. Moreover, the Leishmania transmission did not seem to follow any clear-cut spatial pattern, since large disparities in the seroprevalences of contiguous clusters were found. Curiously, human cases of visceral leishmaniasis have never been observed in some clusters with a relatively high prevalence of canine seroprevalences. Eight parasite isolates from seropositive dogs were found to belong to the same serodeme and zymodeme as Leishmania (L.) chagasi. The implications of these findings with respect to the epidemiology and control of American visceral leishmaniasis are discussed.

Development of eosinophilia in dogs intradermically inoculated with sand fly saliva and Leishmania (Leishmania) Chagasi stationary-phase promastigotes.

Salivary gland lysates of the sand fly Lutzomia longipalpis have been shown to enhance the infectivity of Leishmania in mice. As shown herein, the simultaneous inoculation of Leishmania chagasi stationary-phase promastigotes and L. longipalpis salivary gland lysate by the intradermal route in a group of mongrel dogs induced a statistically significant eosinophilia, in relation to dogs inoculated with Leishmania or with salivary gland lysate only. These dogs had no evidence of infection, in spite of the high infectivity of the promastigotes when inoculated by the intravenous route.