In vivo study of liposomes as drug carriers to oral mucosa using EPR oximetry

The purpose of this study was to select the best types of liposomes for use as drug carriers for topical treatment of oral mucosal lesions. Electron paramagnetic resonance (EPR) oximetry, using the paramagnetic probe lithium phthalocyanine, was used in vivo to measure the effects of a hyperemic drug, benzyl nicotinate (BN) which was incorporated into liposomes of varying size and composition. The liposomes were made from either hydrogenated or non-hydrogenated soy lecithin and mixed with polymethyl methacrylate ointment for application. EPR oximetry was used to measure the partial pressure of oxygen (pO2) in the oral mucosa before and after application of liposomes. It was found that the most pronounced changes of pO2 in oral mucosa and also the longest action of the drug occurred after the topical application of BN in multi-lamellar liposomes made from hydrogenated soy lecithin (p<0.0001). When these liposomes were applied to oral mucosa over 3 successive days it was found that pO2 increased the most on the first day, the effect gradually decreased following application on the second and third days. The duration of the resulting hyperemia was the longest on the second day (p<0.01). Among the examined carriers, multi-lamellar liposomes made from hydrogenated soy lecithin appear to be the most appropriate for local drug delivery to oral mucosa.     

Involvement of serotonergic and dopaminergic mechanisms in hyperthermia induced by a serotonin-releasing drug, p-chloroamphetamine in mice.

Serotonergic and dopaminergic involvement in hyperthermia induced by a serotonin (5-hydroxytryptamine, 5-HT)-releasing drug, p-chloroamphetamine, was investigated in mice. Neither the 5-HT transporter inhibitor fluoxetine nor the 5-HT depleter p-chlorophenylalanine affected p-chloroamphetamine-induced hyperthermia. The dopamine depleter -methyl-p-tyrosine significantly reduced p-chloroamphetamine-induced hyperthermia. The dopamine D₁ receptor antagonist 7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine (SCH 23390) antagonized p-chloroamphetamine-induced hyperthermia, although the dopamine D₂ receptor antagonist sulpiride was without effect. These results indicate that p-chloroamphetamine-induced hyperthermia in mice is mediated by dopamine release followed by activation of the dopamine D₁ receptor.     

Skin oxygenation after topical application of liposome-entrapped benzyl nicotinate as measured by EPR oximetry in vivo: Influence of composition and size

New and improved drug delivery systems are the important subject of much scientific research. The development of formulations that increase skin oxygenation and of methods for measuring oxygen levels in skin are important for dealing with healing processes affected by the level of oxygen. We have use EPR oximetry in vivo to compare the influence of liposomal formulations of different size and composition with that of hydrogel with respect to the action of the entrapped benzyl nicotinate (BN). Following the topical application of BN onto the skin of mice, pO₂ increase was measured by low-frequency EPR as a function of time. The effect of BN was evaluated by 3 different parameters: lag-time, time needed for maximum pO₂ increase, and overall effectiveness expressed by the area under the response-time curve. An increase in skin oxygenation was observed after BN application. The results show that the effect of BN incorporated in liposomes is achieved more rapidly than the effect from hydrophilic gel. The composition of the liposomes significantly affects the time at which BN starts to act and, to a lesser extent, the maximum increase of pO₂ in skin and the effectiveness of BN action. However, the size of the liposomes influences both the effectiveness of BN action and the time at which BN starts to act. After repeated application of liposomes, the pO₂ baseline increased and the response of the skin tissue was faster. Our results demonstrate that EPR oximetry is a useful method for evaluating oxygen changes after drug application and for following the time course of their action.     

Enhanced quinpirole response in rats lesioned neonatally with 5,7-dihydroxytryptamine

The ontogenic destruction of dopamine (DA) neurons in rat brain is associated with supersensitization of DA D₁ receptors. This effect is attenuated when rats are cotreated in ontogeny with the serotonin (5-HT) neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT). In an attempt to determine whether 5-HT fibers might have a similar modulatory role on the sensitivity of the DA D₂ receptor complex, we pretreated rats with desipramine HCl (20 mg/kg IP, base), 1 h before the DA neurotoxin, 6-hydroxydopamine (6-OHDA; 134 μg ICV, base) and/or 5,7-DHT (75 μg ICV) and/or vehicle. At about 3 months after birth dose-effect curves for quinpirole-induced oral activity were constructed for each group of rats. We found that quinpirole, an agonist for the DA D₂ receptor complex, produced a dose-related increase in oral activity in all groups of rats. After a 200 μg/kg dose of quinpirole HCl, however, neonatal 5,7-DHT-lesioned rats had a peak oral response of 54.4 ± 5.1 (mean and SEM) vs. 22.6 ± 4.8 for control rats (p < 0.01). In neonatal 6-OHDA-lesioned rats this dose of quinpirole increased oral activity to 36.8 ± 5.8 oral movements (p < 0.05 vs. control). In rats lesioned with both 5,7-DHT and 6-OHDA, the oral response was not different from control. The enhanced oral response to quinpirole in 5,7-DHT-lesioned rats was attenuated by spiperone, an antagonist for the DA D₂ receptor complex. These findings are believed to be the first to demonstrate that receptors of the DA D₂ complex become sensitized after ontogenic injury to 5-HT fibers. This effect is opposite to the attenuated sensitivity of DA D₁ receptors in rats with a similar 5-HT lesion.     

Dopamine mediation of positive reinforcing effects of amphetamine in stimulant naïve healthy volunteers: results from a large cohort

A positive experience during a first encounter with a drug of abuse is predictive of subsequent use and might represent a vulnerability factor to develop addiction. This paper presents a meta-analysis of data acquired in 60 healthy volunteers who underwent a low-dose amphetamine challenge (0.3 mg/kg, i.v.) during imaging of dopamine D₂ receptor availability with SPECT and the D₂/D₃ radiotracer [¹²³I]IBZM. Amphetamine-stimulated DA release induced a small, significant and highly variable decrease in striatal D₂ receptor availability (−8.3±6.7%). The magnitude of the decrease in D₂ receptor availability was significantly associated with the positive reinforcing effects of the drug reported by the subject (r²=0.14, p=0.003). Age was associated with decreased potency of dopamine to elicit positive reinforcing effects. This study indicates that both a large dopaminergic response and young age during a first encounter with a drug of abuse potential contribute to higher positive reinforcing effects.     

Use of a human liver microsome bank in drug glucuronidation studies

A bank of readily available, well characterized human hepatic microsomal fractions (29 samples from different livers) has been established. The enzymatic characteristics of each microsome sample were determined using three specific UDP-glucuronosyltransferase (UDPGT) substrates (p-nitrophenol for UDPGT₁, 4-hydroxybiphenyl for UDPGT₂A and monodigitoxoside digitoxigenin (DT₁) for UDPGT₇). After characterization, the bank was used to study the phase II biotransformation processes of two drugs: an antiviral, zidovudine (AZT), and an intermediate metabolite of digoxin, monodigitoxoside digoxigenin (DG₁). Results showed a wide interindividual variability for the glucuronidation rate of 4-hydroxybiphenyl, DT₁, AZT and DG₁. Surprisingly, this variability was lower for p-nitrophenol. No significant correlation was found between the various activities except between DG₁ and DT₁ UDPGT activities and 4-hydroxybiphenyl and AZT UDPGT activities. For AZT, further experiments showed that glucuronidation of this antiviral compound was inhibited by 4-hydroxybiphenyl and chloramphenicol but not by morphine, p-nitrophenol, acetaminophen, or bilirubin. Finally, the results strongly suggest the respective involvement of UDPGT₂A and UDPGT₇ in the glucuronidation of AZT and DG₁.     

Effects of a cardiotoxin from Naja naja kaouthia venom on skeletal muscle: involvement of calcium-induced calcium release, sodium ion currents and phospholipases A2 and C.

Snake venom cardiotoxin (CTX) fractions induce contractures of skeletal muscle and hemolysis of red blood cells. The fractions also contain trace amounts of venom-derived phospholipase A₂ (PLA₂) contamination and activate tissue phospholipase C (PLC) activity. The present study examines the mechanisms of action of a CTX fraction from Naja naja kaouthia venom in skeletal muscle. Sphingosine competitively antagonized CTX-induced red blood cell hemolysis, but not skeletal muscle contractures. CTX rapidly lowered the threshold for Ca²⁺-induced Ca²⁺ release in heavy sarcoplasmic reticulum fractions, as monitored with arsenazo III. There was also a slower time-dependent reduction of Na⁺ currents, as assessed by whole cell patch-clamp techniques. The CTX fractions elevated levels of free fatty acids and diacylglycerol for 2 hr in primary cultures of human skeletal muscle by a combined action of venom-derived PLA₂ contamination in the fraction and activation of endogenous PLC activity. The activation of tissue PLC activity could be readily distinguished from the contribution of the venom PLA₂ by p-bromophenacyl bromide treatment of CTX fractions. The mechanism of action involved in contractures of skeletal muscle appears to be related to the immediate and specific effect of CTX (Ca²⁺ release by the sarcoplasmic reticulum), while the mechanisms involved in hemolysis of red blood cells and decreased Na⁺ currents in skeletal muscle most likely relate to long-term effects on lipid metabolism.     

The anxiolytic-like effect of the selective 5-HT6 receptor antagonist SB-399885: the impact of benzodiazepine receptors

The effect of lesion of 5-hydroxytryptamine (5-HT) neurons, produced by p-chloroamphetamine (p-CA; 2 × 10 mg/kg), and the influence of the benzodiazepine receptor antagonist flumazenil (10 mg/kg) on the anticonflict action of N-[3,5-dichloro-2-(methoxy)phenyl]-4-(methoxy)-3-(1-piperazinyl)benzenesulfonamide (SB-399885), a selective 5-HT₆ receptor antagonist, were investigated in the Vogel conflict drinking test in rats. In addition, the interaction between SB-399885 (0.3 mg/kg) and diazepam (2.5 mg/kg) was evaluated in that test. All the compounds tested were administered intraperitoneally. The anticonflict activity produced by SB-399885 (3 mg/kg) was not modified in p-CA-pretreated rats, but it was totally blocked by flumazenil. Combined administration of non-active doses of SB-399885 (0.3 mg/kg) and diazepam (2.5 mg/kg) produced a pronounced anticonflict effect in rats. The present results suggest that the anticonflict activity of SB-399885 is not conditioned by the integrity of 5-HT neurons, and that benzodiazepine receptors are indirectly involved in its effect, possibly due to a functional interaction between 5-HT₆ receptors and the γ-aminobutyric acid (GABA)/benzodiazepine system.     

Thromboxane A(2)-mediated Cl(-) secretion induced by platelet-activating factor in isolated rat colon

Thromboxane A₂ is a novel endogenous secretagogue of Cl⁻ secretion in the distal colon. Here, we examined if the Cl⁻ secretion caused by platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) is mediated by thromboxane A₂ production using isolated mucosae of the rat colon. Furosemide (100 μM) and 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB; 300 μM) completely inhibited PAF (10 μM)-induced increase in short-circuit current (Isc) across the mucosa, indicating that PAF caused a Cl⁻ secretion in the rat colon. A selective thromboxane A₂ receptor antagonist (sodium(E)-11-[2-(5,6-dimethyl-1-benzimidazolyl)-ethylidene]-6,11-dihydrobenz[b,e]oxepine-2-carboxylate monohydrate; KW-3635), and a selective thromboxane synthase inhibitor (sodium 4-[-hydroxy-5-(1-imidazolyl)-2-methylbenzyl]-3,5-dimethylbenzoate dihydrate; Y-20811) inhibited the PAF-induced Cl⁻ current in a concentration-dependent manner. The IC₅₀ values of KW-3635 and Y-20811 were 2.1 and 0.5 μM, respectively. 30 μM KW-3635 and 1 μM Y-20811 inhibited the PAF response by 92% and 83%, respectively. These inhibitors did not affect the prostaglandin E₂-induced increase in Isc. A 5-lipoxygenase-activating protein inhibitor (3-[1-(p-chlorobenzyl)-5-(isopropyl)-3-t-butylthioindol-2-yl]-2,2-dimethyl-propanoic acid sodium; MK-886) (5 μM) did not affect the PAF-induced Cl⁻ current. The present study suggests that the PAF-induced Cl⁻ secretion in the rat colonic mucosa is mainly mediated by a release of thromboxane A₂.     

Nephrotoxicity and uptake of 1-benzyl quinolinium in precision-cut rabbit renal cortical slices

Nephrotoxicity studies have not always meshed toxicity with transport and uptake, although the two are interdependent. To begin to address this issue, a series of model organic cations (quaternary amines) was examined which revealed differences in toxicity that were not explained by slight structural variations. Thus, a single model organic cation, 1-benzyl quinolinium (BQ), was used to assess organic cations in rabbit renal cortical slices. Histopathological evaluation revealed that BQ produced site-specific injury in the S₃ region of the proximal tubule. Biochemical assays (K⁺, qO₂ and ATP) revealed dose- and time-dependent decreases of BQ-exposed slices over 2–12 hr. Cation transport (uptake of tetraethylammonium) was decreased by BQ at sub-toxic doses within 2 hr, although anion transport (uptake of p-aminohippurate) was not affected. Understanding the toxicity and transport of model cations such as BQ will help to identify the mechanisms associated with organic cation nephrotoxicity as well as to facilitate the use of transport parameters to prevent toxicity or prolong drug action of cations.     

Multiple cellular electrophysiological effects of azimilide in canine cardiac preparations

The cellular electrophysiological effect of azimilide (0.1–30 μM) was analyzed in canine ventricular preparations by applying the standard microelectrode and patch-clamp techniques at 37 °C. In papillary muscle, the drug prolonged the action potential duration (APD) in a concentration-dependent manner at a cycle length (CL) of 1000 ms. In Purkinje fibers, at the same CL, the concentration-dependent lengthening of the APD was observed in the presence of up to 3 μM azimilide (at 3.0 μM: 24.1±4.2%, n=9); at higher drug concentration, no further APD prolongation was observed. Azimilide lengthened APD in a reverse frequency-dependent manner in papillary muscle and Purkinje fibers alike. Azimilide (10 μM) caused a rate-dependent depression in the maximal upstroke velocity of the action potential (V_max) in papillary muscle. The time and rate constants of the offset and onset kinetics of this V_max block were 1754±267 ms (n=6) and 5.1±0.4 beats (n=6), respectively. Azimilide did not prevent the APD shortening effect of 10 μM pinacidil in papillary muscle, suggesting that the drug does not influence the ATP-sensitive K⁺ current. Azimilide inhibited the rapid (I_Kr) and slow component (I_Ks) of the delayed rectifier K⁺ current and the L-type Ca²⁺ current (I_Ca). The estimated EC₅₀ value of the drug was 0.59 μM for I_Ks, 0.39 μM for I_Kr and 7.5 μM for I_Ca. The transient outward (I_to) and the inward rectifier (I_k1) K⁺ currents were not influenced by the drug. It is concluded that the site of action of azimilide is multiple, it inhibits not only K⁺ (I_Kr, I_Ks) currents but, in higher concentrations, it also exerts calcium- and use-dependent sodium channel block.     

Zinc-indomethacin complex: Synthesis, physicochemical and biological evaluation in the rat

In continuation of our work on zinc complexes of acidic NSAIDs in order to improve their therapeutic index, zinc complex of indomethacin was synthesised and characterised by IR, NMR, UV, DSC, atomic absorption spectroscopy and elemental analysis. The pH-solubility profile at 25°C and in vitro release pattern at 37°C by dissolution method were determined for the zinc complex and compared with that of indomethacin. Zinc-indomethacin complex showed almost double the solubility and rate of dissolution at pH 6.0 as compared to the parent drug. Anti-inflammatory studies (using carrageenan-induced hind paw edema method) showed that the zinc complex is 2.99-times more potent than indomethacin and 2.55-times more potent than the corresponding physical mixture of indomethacin and zinc sulphate. ANOVA followed by Duncan's new multiple range test indicated a statistically significant difference (p < 0.01) among them. Ulcerogenic effects of the zinc complex were observed at 1.5-times the ED₅₀ of indomethacin as well as at 1.5-times its own ED₅₀, in rats. The lesion indices obtained were compared with that of indomethacin (at 1.5-times its ED₅₀) and control and were statistically evaluated using the Kruskal-Wallis rank test. They were found to be significantly different (p < 0.001). The zinc complex at 1.5-times its own ED₅₀ was found to be the safest with practically no ulcers at all. These studies indicate that the dose of indomethacin and hence its ulcerogenic effects may be reduced appreciably by complexing it with zinc, with no change in its therapeutic action.     

A new sesquiterpene lactone glucoside with inhibitory effect on K562 cells from Ixeris sonchifolia (Bge) Hance

A new minor sesquiterpene lactone glucoside, ixerin Z_A (1), together with 16 known compounds, were isolated from the whole plants of Ixeris sonchifolia (Bge) Hance. The structure of 1 was elucidated as 1(10),3,11(13)-guaiatriene-12,6-olide-2-one-3-O-[6'-(p-metheoxyphenylacetyl)]-β-glucopyranoside on the basis of spectroscopic and chemical evidence. Compound 1 exhibited an inhibitory effect on K₅₆₂ cells.     

Enhanced platelet serotonin 5-HT2A receptor binding in anorexia nervosa and bulimia nervosa.

Some evidence exists to suggest that serotonin 5-HT_2A receptor function is altered in anorexia nervosa and bulimia nervosa. In order to further investigate the 5-HT_2A receptor in eating disorders, platelet [³H]lysergic acid diethylamide ([³H]LSD) binding was studied in ten patients with anorexia nervosa, 23 patients with bulimia nervosa and 33 healthy controls. At admission, B_max for platelet [³H]LSD binding was significantly higher both in the anorexia nervosa group (30.6±4.2 fmol/mg protein; mean±S.D.) and in the bulimia nervosa group (30.8±7.6 fmol/mg protein) than in the control group (23.5 ±6.3 fmol/mg protein; p=0.01 and p=0.003, respectively). K_d was borderline significantly higher among anorexics (median 1.45 nM) and significantly higher among bulimics (median 1.66 nM) than among controls (median 0.95 nM; p=0.05 and 0.003, respectively). The Global Assessment of Functioning score and the body mass index were both significantly negatively correlated to K_d (r=−0.40; p=0.03 and r=−0.41 p=0.03, respectively), but not to B_max. The present study indicates that patients with anorexia nervosa as well as patients with bulimia nervosa have an enhanced 5-HT_2A receptor binding and provides further evidence for a serotonergic dysfunction in eating disorders.     

Comparison of hematologic consequences and efficacy of p-aminophenones in mice

Controlled methemoglobin (MHb) formation is one strategy employed to counter cyanide (CN) toxicity. Currently available MHb formers present certain drawbacks and limitations. The purpose of this study was to characterize, in mice, the hematologic effects of the MHb-forming compound p-aminopropiophenone (PAPP), and two structurally-related p-aminophenones, p-aminoheptanoylphenone (PAHP) and p-aminooctanoylphenone (PAOP). Although these three p-aminophenones have been shown previously to be efficacious as pretreatments against CN, a more complete understanding of their hematologic effects is lacking. In addition, because the active form of PAPP has been shown to be its N-hydroxy metabolite, the N-hydroxy metabolites of PAPP, PAHP and PAOP were also tested. Using a hemoximeter, blood samples obtained −2 to +180 min relative to intramuscular (i.m.) or intraperitoneal (i.p.) drug injections were evaluated. Sodium nitrite (NaNO₂) and the appropriate solvents served as the positive and negative controls, respectively. Dose-, time-, route-, and compound-related effects were observed. MHb and sulfhemoglobin levels increased, whereas levels of those parameters related to oxygen-carrying capacity of the blood, such as, oxygen saturation and oxyhemoglobin decreased. In general, the effects of PAHP and PAOP were longer lasting than those of PAPP and NaNO₂. Furthermore, PAPP and NaNO₂ were equally effective with either route of administration. Conversely, PAHP and PAOP showed larger effects when administered i.p. versus i.m. The animals treated with N-hydroxy metabolites of the p-aminophenones also showed similar changes in the hematological parameters measured. N-hydroxy PAPP was shown to be the most rapidly acting MHb-forming compound examined in this series. It could achieve therapeutic concentrations of MHb within 2 min and thus may be considered as a treatment for CN intoxication. Although additional work is needed, these data provide information that will be useful for the successful development of improved anti-CN MHb formers.     

The influence of metallothionein on exposure to metals: An in vitro study on cellular models

In the present study, the interactions between zinc (Zn) and copper (Cu) or iron (Fe) have been examined. Rat hepatoma cell line H4-II-E-C3, fibroblast cell line mutant MT−/−, and wild-type MT+/+ cells treated with ZnSO₄ or CuSO₄ or FeSO₄ or CuSO₄ + ZnSO₄ or ZnSO₄ + FeSO₄ for different times have been employed to study the effect of metallothionein (MT), glutathione (GSH) and metal (Cu, Fe and Zn) accumulation during cellular adaptation to supraphysiological metal concentrations. To investigate the different biological functions in the processes of metal homeostasis and detoxification, the levels of both MT-1 and MT-2 mRNAs have been evaluated. The three cell lines responded differently to metal treatments suggesting that the uptake and storage of these metals are affected by the specific cellular model and MT presence. In particular, Zn treatment significantly decreased Fe accumulation (p < 0.05), whereas MT induced by Zn increased intracellular Cu content (p < 0.05). Moreover, in H4-II-E-C3 cells administration of metals resulted in a rapid and transient induction of MT (p < 0.05) and in GSH accumulation (p < 0.05) suggesting synergistic interactions in which both appear essential for a protective regulatory function against the redox activity of metals. Taken together these results demonstrate that Zn affects the cellular levels of Cu and Fe by competition with the same ligand sites and/or by coordinate regulation of MT and GSH content.     

Effect of chemical modification with p-bromophenacyl bromide on the enzymatic and lethal properties of phospholipase A2 from Bothrops alternatus (Víbora de la Cruz) venom

, , and . Effect of chemical modification with p-bromophenacyl bromide on the enzymatic and lethal properties of phospholipase A₂ from Bothrops alternatus (Vibora de la Cruz) venom. Toxicon 26, 1137–1144, 1988.—The effects on lethal potency and enzymatic activity were determined following alkylation, with p-bromophenacyl bromide, of the acidic toxic phospholipase A₂ from Bothrops alternatus. The modified B. alternatus enzyme, which lost its enzymatic activity, retained considerable toxicity. Histopathologic studies on mice have demonstrated features similar to those of the native enzyme. However, the distribution of the damage was different and the survival time was longer. It is concluded that the enzyme activity is not important for the lethal action of the enzyme although it influences the distribution of the damage and survival time.     

Antioxidant activity of the oyster mushroom, Pleurotus ostreatus, on CCl4-induced liver injury in rats

This study was undertaken to investigate the putative antioxidant activity of the oyster mushroom Pleurotus ostreatus on CCl₄-induced liver damage in male Wistar rats. Intraperitoneal administration of CCl₄ (2 ml/kg) to rats for 4 days resulted in significantly elevated (p < 0.05) serum levels of glutamic oxaloacetic transaminase (SGOT), glutamic pyruvate transaminase (SGPT) and alkaline phosphatase (SALP) compared to controls. In the liver, significantly elevated levels (p < 0.05) of malondialdehyde (MDA) and lowered levels (p < 0.05) of reduced glutathione (GSH) were observed following CCl₄ administration. Quantitative and qualitative analysis of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (Gpx) revealed lower activities of these antioxidant enzymes in the liver of CCl₄-administered rats. An analysis of the isozyme pattern of these enzymes revealed variations in relative concentration presumably due to hepatotoxicity. When rats with CCl₄-induced hepatotoxicity were treated with the extract of P. ostreatus, the serum SGOT, SGPT and SALP levels reverted to near normal, while the hepatic concentration of GSH, CAT, SOD and Gpx were significantly increased (p < 0.05) and that of MDA significantly (p < 0.05) lowered, when compared to CCl₄-exposed untreated rats. Histopathological studies confirmed the hepatoprotective effect conferred by the extract of P. ostreatus. These results suggest that an extract of P. ostreatus is able to significantly alleviate the hepatotoxicity induced by CCl₄ in the rat.     

Topical application of royal jelly has a healing effect for 5-fluorouracil-induced experimental oral mucositis in hamsters

The aim of this study was to evaluate the effects of bee products such as honey, royal jelly and propolis on 5-fluorouracil-induced experimental oral mucositis in hamsters. Oral mucositis was induced in hamsters through a combination of 5-fluorouracil and mild abrasions that were made on the cheek pouch. Honey, royal jelly and propolis were thereafter topically administered to the oral mucosa, and then the healing process was examined by measuring the size of the mucositis. Honey (1%, 10% and 100%) and propolis (0.3%, 1% and 3%) ointments did not reduce the size of the mucositis in comparison to the vaseline-treated control group. However, the royal jelly (3%, 10% and 30%) ointments significantly improved the recovery from 5-fluorouracil-induced damage in a dose-dependent manner. These results suggest the possibility that the topical application of royal jelly has a healing effect on severe oral mucositis induced by chemotherapy.     

Sulpiride injections in the lateral hypothalamus induce feeding and drinking in rats

Amphetamine injections into the lateral hypothalamus inhibit feeding. This effect is blocked by local administration of neuroleptics, suggesting a role for dopamine in feeding inhibition. However, the type of dopamine receptor involved in satiety is not known. Therefore, we tested the effect of intrahypothalamic injections of sulpiride, a specific D₂ receptor blocker, on amphetamine anorexia in food-deprived rats, and on spontaneous feeding and drinking in satiated rats. Sulpiride attenuated by 36% the anorexia produced by intrahypothalamic injections of amphetamine. In satiated rats, sulpiride (8 μg/0.5 μl) elicited feeding (mean food intake after sulpiride: 5.4 g, and after vehicle 1.6 g, p<0.001), and drinking (mean water intake after sulpiride: 12.3 ml, and after vehicle: 0.9 ml, p<0.001). A dose response relationship was found between sulpiride dose and feeding or drinking. Sulpiride-induced drinking was observed in the absence of food, showing that it is not a postprandial phenomenon. These results suggest that hypothalamic D₂ receptors might be involved in feeding and drinking regulation.