Responses In Ferrets Research Articles

Kinetics of viral replication and induction of host responses in ferrets differs between ocular and intranasal routes of inoculation

While influenza viruses are typically considered respiratory pathogens, the ocular system represents a secondary entry point for virus to establish a productive respiratory infection and the location for rare instances of virus-induced conjunctivitis. We used the ferret model to conduct a side-by-side comparison of virus infectivity, kinetics of viral replication, and induction of host responses following inoculation by either the intranasal or ocular routes with two viruses, A/Netherlands/230/03 (H7N7) and A/Panama/2007/99 (H3N2). We show that ocular inoculation resulted in delayed virus replication and reduced levels of proinflammatory cytokine and chemokine transcript in respiratory tract but not ocular tissues compared with intranasally inoculated animals. We identified numerous proinflammatory mediators with known roles in ocular disease elicited in ferret eye tissue following influenza virus infection. These findings provide a greater understanding of the modulation of host responses following different inoculation routes and underscore the risk associated with ocular exposure to influenza viruses.

Development of chimeric HIV Env immunogens for mucosal delivery with attenuated canine distemper virus (CDV) vaccine vectors

Background Our aim is to develop replication-competent viral vectors for mucosal delivery, which express HIV-Env immunogens that closely mimic the trimeric glycoprotein spike found on HIV particles. We have developed attenuated recombinant CDV (rCDV) expressing SIVmac239-Env and shown that this vector can be used safely to elicit Env-specific immune responses in ferrets and non-human primates through intranasal administration.

The 2009 pandemic H1N1 virus induces anti-neuraminidase (NA) antibodies that cross-react with the NA of H5N1 viruses in ferrets

A miniaturized neuraminidase inhibition (NI) assay using HA-mismatched H6 reassortant viruses was performed to examine the neuraminidase (NA)-specific antibody response in ferrets immunized with live-attenuated influenza vaccine (LAIV) strains. The strains tested possessed different NAs derived from seasonal H1N1 and H3N2, 2009 pandemic H1N1, and the highly pathogenic influenza H5N1 virus. The anti-NA antibodies from the 2009 pandemic strain (A/California/7/2009) immunized ferrets cross-reacted with the NA of H5N1 but not with the NA of seasonal H1N1 viruses. The plaque size reduction assay confirmed the cross-reactivity between the NAs of A/California/7/2009 and the H5N1 virus. Sequence and structural analyses of these N1 NA proteins showed that the NA of the 2009 pandemic H1N1 strain shared at least 22 more amino acids in the head domain with the NAs of the avian H5N1 strains than with the NAs of seasonal human H1N1 viruses. Our data demonstrated LAIV-induced NA antibody responses in ferrets and cross-reactive NA antibodies induced by 2009 pandemic H1N1 and H5N1 LAIV viruses.

Usefulness of Olanzapine as an Adjunct to Opioid Treatment and for the Treatment of Neuropathic Pain

The use of opioids for pain management is often associated with nausea and vomiting. Although conventional antipsychotics are often used to counter emesis, they can be associated with extrapyramidal symptoms. However, chronic pain can induce sleep disturbance. The authors investigated the effects of the atypical antipsychotic olanzapine on morphine-induced emesis and the sleep dysregulation associated with chronic pain. A receptor binding assay was performed using mouse whole brain tissue. The emetic response in ferrets was evaluated by counting retching and vomiting behaviors. Catalepsy in mice was evaluated by placing both of their forepaws over a horizontal bar. Released dopamine was measured by an in vivo microdialysis study. Sleep disturbance in mice in a neuropathic pain-like state was assayed by electroencephalogram and electromyogram recordings. Olanzapine showed high affinity for muscarinic M1 receptor in brain tissue. Olanzapine decreased morphine-induced nausea and vomiting in a dose-dependent manner. However, olanzapine at a dose that had an antiemetic effect (0.03 mg/kg) did not induce catalepsy or hyperglycemia. In addition, olanzapine at this dose had no effect on the morphine-induced release of dopamine or inhibition of gastrointestinal transit. Finally, olanzapine inhibited thermal hyperalgesia and completely alleviated the sleep disturbance induced by sciatic nerve ligation. These findings suggest that olanzapine may be useful for the treatment of morphine-induced emesis and as an adjunct for the treatment of neuropathic pain associated with sleep disturbance.

Effects of the new benzimidazole derivative TAS-203, an orally active phosphodiesterase 4 inhibitor, on airway inflammation in rats and emetic responses in ferrets

TAS-203 (2-[3-(cyclopropylmethoxy)-4-methoxyphenyl]-5-(1H-1,2,4-triazol-1-yl)-1H-benzimidazole, CAS 223909-92-0) is a novel phosphodiesterase 4 (PDE4) inhibitor that has been found to have good anti-inflammatory effects and low emetogenic activity in vivo. In the present studies, the anti-inflammatory profile of TAS-203 was examined and compared with that of cilomilast (CAS 153259-65-5), the most advanced PDE4 inhibitor. TAS-203 inhibited the activity of purified human PDE4 with an IC50 value of 88 nM and also the recombinant PDE4 subtypes (4A, 4B, 4C and 4D) with respective IC50 values of 47, 35, 227 and 43 nM. In the experiments using inflammatory cells, TAS-203 concentration-dependently inhibited platelet-activating factor-induced eosinophil chemotaxis and lipopolysaccharide (LPS)-stimulated tumor necrosis factor-a release from human monocytes with respective IC50 values of 250 and 38.5 nM. For airway inflammation, TAS-203 at 10 mg/kg and cilomilast at 30 mg/kg significantly inhibited antigen-induced airway eosinophilia and LPS-induced airway neutrophilia in rats. The emetogenicity of TAS-203 and cilomilast was evaluated in a ferret model of emesis. The maximum dose of TAS-203 not carrying emesis was 100 mg/kg, while that of cilomilast was less than 10 mg/kg. Finally, TAS-203 was found to be poorly distributed to the brain after oral administration of 10 mg/kg TAS-203 in rats. These results indicate that TAS-203 is an orally active PDE4 inhibitor with potent anti-inflammatory activities and low emetogenicity that may be useful in the treatment of airway inflammatory conditions such as asthma and chronic obstructive pulmonary disease.

Vaccine-specific antibody secreting cells are a robust early marker of LAIV-induced B-cell response in ferrets

Currently, a robust set of immune correlates for live attenuated influenza vaccine (LAIV) efficacy in humans has not been fully elucidated. The serum hemagglutination inhibition (HAI) assay has been historically used to measure humoral immune responses to injectable inactivated influenza vaccination. However, serum antibody titers do not reliably reflect the complete mechanism of action of LAIV, which is an intranasally delivered vaccine and is expected to induce local mucosal and cellular immune responses in addition to humoral immune responses. Therefore, we designed a study to evaluate potential immune correlates of LAIV vaccination in the ferret animal model of influenza infection. Ferrets were vaccinated with increasing doses of LAIV and four weeks later challenged with a homologous wild-type (wt) H1N1 strain. Humoral immune responses measured following LAIV vaccination included HAI, serum antibodies and antibody secreting cells (ASC); and the responses were found to correlate with the dose level of LAIV administered in this model. Protection from wt virus challenge was determined by measuring inhibition of wt viral replication in nasal washes and in lung tissue. Results demonstrated that LAIV doses ≥ 5.0 log(10) Plaque Forming Units (PFU) elicited vaccine-specific IgG and IgA ASC frequencies and induced complete protection in the lungs. Further, we developed a novel model utilizing seropositive older ferrets to demonstrate that in the background of previous wt influenza infection LAIV induces a robust vaccine-specific B-cell response even in the absence of serum antibody response, a result that suggests that effector B-cell responses generated by LAIV are not inhibited by prior viral exposure. Finally, we demonstrated that LAIV elicits strain-specific memory B-cell responses that are measurable in a background of wt influenza infections. Taken together, results from these studies identified the antigen-specific ASC frequency as a useful early biomarker of LAIV-induced B-cell immune response.

Virulence differences of closely related pandemic 2009 H1N1 isolates correlate with increased inflammatory responses in ferrets

Several early pandemic H1N1 influenza isolates cause severe disease in different animals models, while most strains result in mild clinical signs similar to seasonal influenza. In this study, the pathogenesis of the virulent Mexican isolate A/Mexico/InDRE4487/2009 and a mild Canadian isolate A/Canada-AB/RV1532/2009 was compared in ferrets. These viruses differed at nine residues, none of which has been previously identified as virulence factor. The Mexican isolate caused more severe disease and higher mortality, and reached higher peak nasal wash titers. Both viruses grew similarly in the respiratory tract, but only the virulent virus was detected in the gut after day 3. During the acute phase, both strains caused similar lung pathology, however the Mexican isolate induced severe inflammation even after virus clearance. This virus was also associated with a rapid and sustained induction of inflammatory cytokines, indicating that early dysregulation of the host response contributes importantly to the disease outcome.

CAF01 potentiates immune responses and efficacy of an inactivated influenza vaccine in ferrets.

Trivalent inactivated vaccines (TIV) against influenza are given to 350 million people every year. Most of these are non-adjuvanted vaccines whose immunogenicity and protective efficacy are considered suboptimal. Commercially available non-adjuvanted TIV are known to elicit mainly a humoral immune response, whereas the induction of cell-mediated immune responses is negligible. Recently, a cationic liposomal adjuvant (dimethyldioctadecylammonium/trehalose 6,6′-dibehenate, CAF01) was developed. CAF01 has proven to enhance both humoral and cell-mediated immune responses to a number of different experimental vaccine candidates. In this study, we compared the immune responses in ferrets to a commercially available TIV with the responses to the same vaccine mixed with the CAF01 adjuvant. Two recently circulating H1N1 viruses were used as challenge to test the vaccine efficacy. CAF01 improved the immunogenicity of the vaccine, with increased influenza-specific IgA and IgG levels. Additionally, CAF01 promoted cellular-mediated immunity as indicated by interferon-gamma expressing lymphocytes, measured by flow cytometry. CAF01 also enhanced the protection conferred by the vaccine by reducing the viral load measured in nasal washes by RT-PCR. Finally, CAF01 allowed for dose-reduction and led to higher levels of protection compared to TIV adjuvanted with a squalene emulsion. The data obtained in this human-relevant challenge model supports the potential of CAF01 in future influenza vaccines.

Pandemic H1N1 influenza virus causes a stronger inflammatory response than seasonal H1N1 influenza virus in ferrets

A 2009 H1N1 influenza virus pandemic, which had its origin in swine, caused severe illness and mortality in humans. Inflammatory responses may be responsible for pathogenesis caused by infection with influenza viruses. To better understand the pathogenic mechanism, clinical signs and inflammatory responses in ferrets infected with the pandemic H1N1 were compared with those caused by seasonal H1N1 influenza virus. Ferrets infected with the 2009 pandemic H1N1 virus displayed higher body temperatures, greater reduction in body weight, and higher viral titers in the tracheae and lungs. Levels of inflammatory cytokines, including interleukin-6, interferon-alpha, and tumor necrosis factor-alpha, were higher in the lungs of ferrets infected with the 2009 pandemic H1N1. The data support the idea that increased pathogenesis caused by the 2009 pandemic H1N1 influenza virus may have been partially mediated by a higher induction of pro-inflammatory cytokines in the lungs of affected humans or animals.

Pandemic influenza 1918 H1N1 and 1968 H3N2 DNA vaccines induce cross-reactive immunity in ferrets against infection with viruses drifted for decades

Please cite this paper as: Bragstad et al. (2010) Pandemic influenza 1918 H1N1 and 1968 H3N2 DNA vaccines induce cross‐reactive immunity in ferrets against infection with viruses drifted for decades. Influenza and Other Respiratory Viruses 5(1), 13–23. Background Alternative influenza vaccines and vaccine production forms are needed as the conventional protein vaccines do not induce broad cross‐reactivity against drifted strains. Furthermore, fast vaccine production is especially important in a pandemic situation, and broader vaccine reactivity would diminish the need for frequent change in the vaccine formulations. Objective In this study, we compared the ability of pandemic influenza DNA vaccines to induce immunity against distantly related strains within a subtype with the immunity induced by conventional trivalent protein vaccines against homologous virus challenge. Methods Ferrets were immunised by particle‐mediated epidermal delivery (gene gun) with DNA vaccines based on the haemagglutinin (HA) and neuraminidase (NA) and/or the matrix (M) and nucleoprotein genes of the 1918 H1N1 Spanish influenza pandemic virus or the 1968 H3N2 Hong Kong influenza pandemic virus. The animals were challenged with contemporary H1N1 or H3N2 viruses. Results We demonstrated that DNA vaccines encoding proteins of the original 1918 H1N1 pandemic virus induced protective cross‐reactive immune responses in ferrets against infection with a 1947 H1N1 virus and a recent 1999 H1N1 virus. Similarly, a DNA vaccine, based on the HA and NA of the 1968 H3N2 pandemic virus, induced cross‐reactive immune responses against a recent 2005 H3N2 virus challenge. Conclusions DNA vaccines based on pandemic or recent seasonal influenza genes induced cross‐reactive immunity against contemporary virus challenge as good as or superior to contemporary conventional trivalent protein vaccines. This suggests a unique ability of influenza DNA to induce cross‐protective immunity against both contemporary and long‐time drifted viruses.

Oseltamivir-Resistant Pandemic A/H1N1 Virus Is as Virulent as Its Wild-Type Counterpart in Mice and Ferrets

The neuraminidase inhibitor oseltamivir is currently used for treatment of patients infected with the pandemic A/H1N1 (pH1N1) influenza virus, although drug-resistant mutants can emerge rapidly and possibly be transmitted. We describe the characteristics of a pair of oseltamivir-resistant and oseltamivir-susceptible pH1N1 clinical isolates that differed by a single change (H274Y) in the neuraminidase protein. Viral fitness of pH1N1 isolates was assessed in vitro by determining replication kinetics in MDCK α2,6 cells and in vivo by performing experimental infections of BALB/c mice and ferrets. Despite slightly reduced propagation of the mutant isolate in vitro during the first 24 h, the wild-type (WT) and mutant resistant viruses induced similar maximum weight loss in mice and ferrets with an identical pyrexic response in ferrets (AUC of 233.9 and 233.2, P = 0.5156). Similarly, comparable titers were obtained for the WT and the mutant strains on days 1, 3, 6 and 9 post-infection in mouse lungs and on days 1–7 in ferret nasal washes. A more important perivascular (day 6) and pleural (days 6 and 12) inflammation was noted in the lungs of mice infected with the H274Y mutant, which correlated with increased pulmonary levels of IL-6 and KC. Such increased levels of IL-6 were also observed in lymph nodes of ferrets infected with the mutant strain. Furthermore, the H274Y mutant strain was transmitted to ferrets. In conclusion, viral fitness of the H274Y pH1N1 isolate is not substantially altered and has the potential to induce severe disease and to disseminate.

The 2009 H1N1 Pandemic Adds to Our Knowledge of Influenza Pathogenesis

This commentary discusses the pathology and pathogenesis of the 2009 H1N1 influenza A pandemic.

A single immunization with CoVaccine HT-adjuvanted H5N1 influenza virus vaccine induces protective cellular and humoral immune responses in ferrets.

Highly pathogenic avian influenza A viruses of the H5N1 subtype continue to circulate in poultry, and zoonotic transmissions are reported frequently. Since a pandemic caused by these highly pathogenic viruses is still feared, there is interest in the development of influenza A/H5N1 virus vaccines that can protect humans against infection, preferably after a single vaccination with a low dose of antigen. Here we describe the induction of humoral and cellular immune responses in ferrets after vaccination with a cell culture-derived whole inactivated influenza A virus vaccine in combination with the novel adjuvant CoVaccine HT. The addition of CoVaccine HT to the influenza A virus vaccine increased antibody responses to homologous and heterologous influenza A/H5N1 viruses and increased virus-specific cell-mediated immune responses. Ferrets vaccinated once with a whole-virus equivalent of 3.8 microg hemagglutinin (HA) and CoVaccine HT were protected against homologous challenge infection with influenza virus A/VN/1194/04. Furthermore, ferrets vaccinated once with the same vaccine/adjuvant combination were partially protected against infection with a heterologous virus derived from clade 2.1 of H5N1 influenza viruses. Thus, the use of the novel adjuvant CoVaccine HT with cell culture-derived inactivated influenza A/H5N1 virus antigen is a promising and dose-sparing vaccine approach warranting further clinical evaluation.

The impact of key amino acid substitutions in the hemagglutinin of influenza A (H3N2) viruses on vaccine production and antibody response

Influenza H3N2 viruses have recently drifted from A/Wisconsin/67/05-like to A/Brisbane/10/07-like viruses. The effect of key amino acid substitutions in the hemagglutinin (HA) protein on the replication, antigenicity and immunogenicity of cold-adapted, live attenuated vaccine strains was examined. A/Brisbane/10/07 egg isolate contained a unique combination of G186 and P194 which were required for efficient virus growth in Madin–Darby Canine Kidney (MDCK) cells and embryonated chicken eggs, but the virus induced low level of serum antibody response in ferrets. Substitution of the G186 and P194 in the HA of A/Brisbane/10/07 by V186 and L194 that were present in the HA of A/Wisconsin/67/05-like viruses significantly impaired virus replication but greatly improved the immunogenicity of the vaccine virus to a level comparable to that elicited by the A/Wisconsin/67/05 vaccine. The replication of the variants with impaired growth could be improved by amino acid substitutions at the 195 or 226 residues. The viruses with the G186 and P194 residues were antigenically distinct from the viruses with V186 and L194. Sequence analysis of the HA sequences of the H3N2 viruses from the database and sequencing of the HA gene of a cell-derived A/Brisbane/10/07-like virus before and after egg passage indicated that the P194 residue was most likely derived from egg adaptation. Our results demonstrated the importance of careful evaluation of vaccine strains to ensure that the selected vaccines not only replicate well in eggs, but also retain their antigenicity and are immunogenic in the host.

Modeling host responses in ferrets during A/California/07/2009 influenza infection

Immune responses during infection with pandemic H1N1 2009 influenza A virus (2009-H1N1) are still poorly understood. Using an experimental infection model in ferrets, we examined the pathological features and characterized the host immune responses by using microarray analysis, during infection with 2009-H1N1 A/California/07/2009 and seasonal A/Brisbane/59/2007. Chemokines CCL2, CCL8, CXCL7 and CXCL10 along with the majority of interferon-stimulated genes were expressed early, correlated to lung pathology, and abruptly decreased expression on day 7 following infection of A/California/07/2009. Interestingly, the drop in innate immune gene expression was replaced by a significant increase of the adaptive immune genes for granzymes and immunoglobulins. Serum anti-influenza antibodies were first observed on day 7, commensurate with the viral clearance. We propose that lung pathology in humans occurs during the innate phase of host immunity and a delay or failure to switch to the adaptive phase may contribute to morbidity and mortality during severe 2009-H1N1 infections.

H5N1 Vaccine-Specific B Cell Responses in Ferrets Primed with Live Attenuated Seasonal Influenza Vaccines

BackgroundLive attenuated influenza H5N1 vaccines have been produced and evaluated in mice and ferrets that were never exposed to influenza A virus infection (Suguitan et al., Plos Medicine, e360:1541, 2006). However, the preexisting influenza heterosubtypic immunity on live attenuated H5N1 vaccine induced immune response has not been evaluated.Methodology and Principal FindingsPrimary and recall B cell responses to live attenuated H5N1 vaccine viruses were examined using a sensitive antigen-specific B cell ELISpot assay to investigate the effect of preexisting heterosubtypic influenza immunity on the development of H5N1-specific B cell immune responses in ferrets. Live attenuated H5N1 A/Hong Kong/213/03 and A/Vietnam/1203/04 vaccine viruses induced measurable H5-specific IgM and IgG secreting B cells after intranasal vaccination. However, H5-specific IgG secreting cells were detected significantly earlier and at a greater frequency after H5N1 inoculation in ferrets previously primed with trivalent live attenuated influenza (H1N1, H3N2 and B) vaccine. Priming studies further revealed that the more rapid B cell responses to H5 resulted from cross-reactive B cell immunity to the hemagglutinin H1 protein. Moreover, vaccination with the H1N1 vaccine virus was able to induce protective responses capable of limiting replication of the H5N1 vaccine virus to a level comparable with prior vaccination with the H5N1 vaccine virus without affecting H5N1 vaccine virus induced antibody response.ConclusionThe findings indicate that previous vaccination with seasonal influenza vaccine may accelerate onset of immunity by an H5N1 ca vaccine and the heterosubtypic immunity may be beneficial for pandemic preparedness.

A plant‐produced influenza subunit vaccine protects ferrets against virus challenge

Influenza A viruses are of major concern for public health, causing worldwide epidemics associated with high morbidity and mortality. Vaccines are critical for protection against influenza, but given the recent emergence of new strains with pandemic potential, and some limitations of the current production systems, there is a need for new approaches for vaccine development. To demonstrate the immunogenicity and protective efficacy of plant-produced influenza antigens. Method We engineered, using influenza A/Wyoming/3/03 (H3N2) as a model virus, the stem and globular domains of hemagglutinin (HA) produced in plants as fusions to a carrier protein and used purified antigens with and without adjuvant for ferret immunization. These plant-produced antigens were highly immunogenic and conferred complete protection against infection in the ferret challenge model. The addition of plant-produced neuraminidase was shown to enhance the immune response in ferrets. Plants can be used as a production vehicle for vaccine development against influenza. Domains of HA can generate protective immune responses in ferrets.

Severe Acute Respiratory Syndrome Coronavirus Infection in Vaccinated Ferrets

Background. Development of vaccines to prevent severe acute respiratory syndrome (SARS) is limited by the lack of well-characterized animal models. Previous vaccine reports have noted robust neutralizing antibody and inflammatory responses in ferrets, resulting in enhanced hepatitis. Methods. We evaluated the humoral immune response and pathological end points in ferrets challenged with the Urbani strain of SARS-associated coronavirus (SARS-CoV) after having received formalin-inactivated whole-virus vaccine or mock vaccine. Results. Humoral responses were observed in ferrets that received an inactivated virus vaccine. Histopathological findings in lungs showed that infection of ferrets produced residual lung lesions not seen in both mock and vaccinated ferrets. SARS-CoV infection demonstrated bronchial and bronchiolar hyperplasia and perivascular cuffing in ferret lung tissue, as seen previously in infected mice. No evidence of enhanced disease was observed in any of the ferrets. All of the ferrets cleared the virus by day 14, 1 week earlier if vaccinated. Conclusions. The vaccine provided mild immune protection to the ferrets after challenge; however, there was no evidence of enhanced liver or lung disease induced by the inactivated whole-virus vaccine. The ferret may provide another useful model for evaluating SARS vaccine safety and efficacy.

Purinergic P2X receptor activation induces emetic responses in ferrets and Suncus murinus (house musk shrews)

Despite the rapid progress made in understanding the significant role played by signalling via extracellular ATP in physiology and pathology, there has been no clear information generated on its involvement in the emetic response. In the present study, the emetogenic potential of extracellular ATP signalling in mammalian species was examined using ferrets and Suncus murinus (house musk shrews). A slowly degradable ATP analogue, alpha,beta-methyleneATP (alpha,beta-meATP), was used to activate the P2X receptors, and either the non-selective P2 receptor antagonist, pyridoxal phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS), or the specific P2X(3) homomer and P2X(2/3) heteromer antagonist, A-317491, were tested against the agonist-induced response. Intraperitoneal injection of alpha,beta-meATP produced significant emetic responses in ferrets (1 - 30 mg kg(-1)) and in Suncus murinus (5 - 50 mg kg(-1)). The responses occurred frequently within the first 10 min after administration, much less frequently from 11 to 60 min and no responses occurred later than 60 min. The emetic responses were completely inhibited by intraperitoneal pre-treatment with PPADS (100 mg kg(-1)) or A-317491 (100 mg kg(-1)). Abdominal surgical vagotomy did not reduce the emetic response in Suncus murinus significantly. These results for the first time indicate that the activation of P2X receptors evokes emetic responses in mammalian species. The P2X(3) homomer and.or P2X(2/3) heteromer in the area postrema could be responsible for the emetic response. This finding contributes to the elucidation of the roles played by extracellular ATP signalling in various emetic symptoms.

The advantages of fentanyl for the treatment of pain: Studies of pharmacological profiles and fentanyl relatedside effects

The understanding of the pharmacological profiles of fentanyl and fentanyl-related side effects seems to be critical for the management for control of pain. Therefore, the present study was designed to investigate the advantages for treatment with fentanyl and the side effects such as emesis and gastrointestinal transit inhibition. The results demonstrated that fentanyl produced a profound antinociception in ferrets and mice than that induced by morphine. These findings are consistent with the experiences in the clinic. Morphine with lower doses than antinociceptive doses, produced a significant increase in gastrointestinal transit inhibition. However, fentanyl produced no gastrointestinal transit inhibition unlike morphine. These findings are consistent with the clinical experiences in the use of fentanyl. The clinical studies in patients chronic cancer pain showed that transdermal therapeutic delivery system for fentanyl (TTS-fentanyl) produces less side effects such as constipation, nausea and vomiting than that induced by oral morphine. Morphine with lower doses than that used for antinociceptive assay also produced either in the number of retching or vomiting. However, fentanyl failed to produce emetic response in ferrets. These findings indicate that fentanyl produces much less emesis than that induced by morphine. Finally, we conclude that fentanyl produced potent antinociception in ferrets and mice. In addition, fentanyl produced much less side effects including emesis and constipation. These findings may provide evidence for benefit and usefulness of fentanyl for clinical frame on the management of pain treatment. Key word: fentanyl; antinociception; emesis; ferret.