Factors associated with high-risk human papillomavirus infection and high-grade cervical neoplasia: A population-based study in Paraguay.

BACKGROUND: Cervical cancer (CC) is one of the leading causes of cancer mortality among women from Paraguay, with high incidence and mortality rates (31.2 and 16 per 100 000 women, respectively). Although the risk factors associated with high-risk human papillomavirus (hrHPV) infection and preneoplastic cervical lesions are widely studied, population-based characteristics of particular settings may influence the feasibility of HPV-based CC screening implementation. This study aimed to explore factors associated with hrHPV infection and high-grade cervical neoplasia in hrHPV-positive (hrHPV+) women from Paraguay. METHODS: A total of 5677 women aged 30-64 years from the Central Department of Paraguay were screened with HPV test (Hybrid Capture 2) and Pap smear. Sociodemographic and risk factor interviews were conducted. hrHPV+ women were referred to colposcopy and women with an abnormal colposcopy had a biopsy taken. The outcomes recorded were the hrHPV status and the presence of high-grade cervical intraepithelial neoplasia or worse (CIN2+) among hrHPV+ women. Associations were investigated using multivariate logistic regressions. RESULTS: hrHPV prevalence was 13.8% (95%CI 13.0-14.8). This value decreased with the age of women (p-trend<0.001) and increased with the lifetime number of sexual partners (p-trend<0.001) and number of previous female partners of their current male partner if women had had one lifetime sexual partner (p-trend<0.001), increasing from 3.06 (95%CI 0.073-20.9) if partners had had one previous female partner to 9.19 (95%CI 2.36-61.1) if they had had eight or more. In hrHPV+ women, CIN2+ prevalence was 10.7% (95%CI 8.58-13.2) and increased with time since the last Pap smear (p-trend<0.001) and with the increasing number of pregnancies (p-trend = 0.05). CONCLUSION: In these settings, the sexual behavior of women and their male partners is associated with hrHPV infection. In hrHPV+ women, underscreening practices and multiple pregnancies are associated with CIN2+. This knowledge can contribute to public health policies for CC prevention and control in Paraguay.

Conocimientos, actitudes y prácticas sobre virus de papiloma humano (VPH) y cáncer de cuello uterino en mujeres de 30 y más años de edad, de un barrio ribereño de Asunción, (Bañado Sur). 2012 / Knowledge, attitudes and practice on human papilloma virus (HPV) and cervix cancer in women who were 30 years old or more, from a riverside neighborhood of Asuncion, (Bañado Sur). 2012

Introducción: El cáncer de cuello uterino es un problema de salud pública en Paraguay. Objetivo: Determinar conocimientos, actitudes y prácticas sobre virus del papiloma humano (VPH) y cáncer de cuello uterino en mujeres de 12 Unidades de Salud Familiar (USF) de Bañado Sur-Asunción, periodo abril-octubre 2012. Metodología: Estudio descriptivo de corte transversal, utilizando cuestionario estructurado autoadministrado. Resultados: La edad promedio de las encuestadas fue 42 años, la mayoría en unión libre o casadas (70%); 65% tienen educación básica y media, 56% son amas de casa. El 83% tienen seguro médico; 78% escuchó hablar sobre cáncer de cuello uterino, 74% de éstas en los centros de salud. El 10% de las encuestadas conoce el VPH y lo relaciona con la enfermedad, 90 % escuchó hablar sobre la prueba de Papanicolaou, el 27 % de ellas sabe en qué consiste; 90% de las mujeres demostró actitud favorable y 56% prácticas favorables respecto a la prevención de la enfermedad. Conclusiones: El estudio permite conocer la percepción que tiene una población de mujeres de un barrio marginal de la capital del país, respecto al cáncer de cuello uterino y el principal factor de riesgo que lo produce, a fin de incrementar la prestación de servicios de prevención de este tipo de cáncer, además de propiciar el trabajo interinstitucional e intersectorial en la prevención y control de la enfermedad en el país.

Introduction: Cervix cancer is a public health problem in Paraguay. Objective: To determine knowledge, attitudes and practices on human papilloma virus (HPV) and uterine cervix cancer in women from 12 Family Health Units (FHU) of the Bañado Sur- Asunción, April-October 2,012 period. Methodology: Descriptive cross-sectional study that used self-administered structured questionnaires. Results: The mean age was 42 years, most of them cohabitated or were married (70%); 65% had elementary and secondary education and 56% was housewife; 83% had medical insurance and 78% heard about uterine cervix cancer, 74% of them in health posts. Only 10% knew HPV and related it to a disease, 90% heard about Papanicolaou test, but only 27% knew what is, 90% showed favorable attitude and 56% favorable practices in relation to the disease prevention. Conclusions: The study provided information on the perception that a population of women from a marginal zone of the capital have in relation to cervical cancer and its main risk factor. This will allow increasing the supply of prevention services for this type of cancer, along with promoting inter-institutional and inter-sectorial work on the prevention and control of this disease in the country.

Estado nutricional y aspectos alimentarios de mujeres indígenas del departamento de Presidente Hayes, Paraguay / Nutritional state and food aspects of indigenous women from Presidente Hayes department, Paraguay

Introducción: Las comunidades indígenas presentan un mayor riesgo de inseguridad alimentaria y malnutrición, menor disponibilidad de recursos, y una creciente dependencia de alimentos más baratos aunque con un alto grado de procesamiento. Objetivo: Identificar el estado nutricional y aspectos alimentarios en mujeres indígenas de tres comunidades del Departamento de Presidente Hayes, Chaco Paraguayo. Metodología: Estudio observacional de diseño transversal con componente analítico, que incluyó a 81 mujeres de 15 a 44 años de edad, de las etnias Maká y Toba Qom. Previo consentimiento informado, se realizó la valoración nutricional y la entrevista para obtener los datos sociodemográficos y alimentarios. Resultados: Las mujeres indígenas presentaron una frecuencia de sobrepeso de 30,8% y obesidad del 21,0%, mientras que el 1,2 % presentó desnutrición. No encontramos diferencia significativa entre las etnias, en relación al sobrepeso y obesidad, (p>0,05). Observamos que las indígenas tenían una alta ingesta de frutas, azúcares y mieles. El 87 y 88% de las mujeres indígenas de ambas etnias estudiadas refirieron no consumir lácteos y derivados y entre 65 y 69% refirieron no consumir verduras. Conclusiones: Observamos un elevado porcentaje de obesidad y sobrepeso, un bajo consumo de lácteos y verduras y un alto consumo de azúcares, relacionados posiblemente a cambios en los aspectos alimentarios y sus costumbres, influenciados por la cercanía a las zonas urbanas y el acceso a alimentos de menor precio y mayor contenido energético.

Introduction: Indigenous communities present higher risk of food insecurity and malnutrition, lower availability of resources and growing dependence on cheaper food but with high degree of processing. Objective: To identify the nutritional state and food aspects in indigenous women from three communities of Presidente Hayes Department, Paraguayan Chaco. Methodology: Cross-sectional observational study with analytical component including 81 women who were 15 to 44 years old from the Maká and Toba Qom ethnic groups. After giving their informed consent, the nutritional assessment and the interview to collect socio-demographic and food data were carried out. Results: The indigenous women presented an overweight frequency of 30.8 % and obesity of 21.0%, while malnutrition was observed in 1.2%. No significant differences were found between ethnic groups in relation to overweight and obesity (p>0.05). High ingestion of fruits, sugar and honey was observed and 87% and 88% of the indigenous women from both ethnic groups referred that they did not consume dairy products and derivatives and 65% and 69% referred that they did not consume vegetables. Conclusions: High percentages of obesity and overweight were observed. Low consumption of dairy products, its by products and vegetables and a high consumption of sugar were observed, related probably to changes in food aspects and the habits of these groups, influenced by the proximity to urban areas and the access to low prices food with high energetic content.

Distribution of human papillomavirus (HPV) genotypes and bacterial vaginosis presence in cervical samples from Paraguayan indigenous.

OBJECTIVE: To determine the frequency of human papillomavirus (HPV) types and to assess bacterial vaginosis (BV) possible associations with cervical infections in indigenous Paraguayan women of the Department of Presidente Hayes. METHODS: This study included 181 sexually active women without cervical lesions. HPV typing was performed by polymerase chain reaction with primers PGMY 09/11 followed by reverse line hybridization. BV was diagnosed by the Nugent criteria using the results from a Gram stain smear. RESULTS: Sixteen percent of women were positive for at least one high risk HPV type (HR-HPV). The most frequent genotypes were HPV 16 (4.4%), followed by HPV 58 (3.3%), HPV 45 (3.3%), HPV 53 (2.8%) and HPV 11 (2.8%). A significant association between HR-HPV and BV was observed (p=0.01). In addition, women with BV had a higher frequency of Chlamydia trachomatis (p=0.0007), Trichomonas vaginalis (p=0.00009), Mycoplasma hominis (p=0.001). CONCLUSIONS: A large variety of HPV genotypes was detected and showed a slightly different pattern from previous studies on urban women in Paraguay, with the predominance of HR-HPV. Furthermore, the information of co-infections involved in BV could be useful for the improvement of national prevention programs, as well as for laboratory surveillance of these genital infections.

Una propuesta rápida y económica para detectar el virus de papiloma humano por PCR a partir de muestras cervicales con reactivo desnaturalizante / A rapid and economic option for human papillomavirus detection by PCR in cervical samples with denaturing reagent

Trabajos han demostrado la utilidad de la captura híbrida II (CH II®) en la detección del virus de papiloma humano de alto riesgo oncogénico (HR-HPV) como método de tamizaje primario para detección de cáncer de cuello uterino, así como las bondades de la PCR que permite acceder a métodos de tipificación viral. Por ello el objetivo fue detectar el genoma del HPV por PCR a partir de muestras de CH II® cien veces diluidas. Estudio transversal en 141 muestras cervicales de mujeres con citología normal y anormal que concurrieron al IICS, UNA. Las muestras fueron procesadas por CH II® y almacenadas con reactivo desnaturalizante a -80ºC. Luego, las muestras fueron diluidas 100 veces con agua destilada y posteriormente procesadas por PCR. Se detectó HPV en 51% y 43% de las muestras analizadas por CH II® y PCR, respectivamente. Diecisiete de 23 muestras positivas por CH II® con carga viral relativa baja fueron negativas por PCR. Esto podría deberse a la degradación del material. Además, 6 muestras negativas por CH II® fueron positivas por PCR sugiriendo presencia de infección con tipos virales no incluidos en CH II® . Estos resultados sugieren que es posible realizar la detección de HPV por PCR en muestras procesadas por CH II® previa dilución. Esta propuesta rápida, sencilla y económica, minimiza el riesgo de perder el material genético en la extracción y permite acceder a métodos de tipificación viral que podrían contribuir con datos sobre tipos de HPV circulantes para realizar una vigilancia en la era post-vacunal.

Studies havedemonstrated the usefulness of the hybrid capture II (CHII) in thedetection of oncogenic high risk human papillomavirus (HR-HPV) asaprimaryscreeningmethod for detection of cervical cancer, as well as the benefits of PCR that allows accessto viral typing methods. The objective was todetect HPV by PCR from cervical samplesprocessed by CH II.It was a cross-sectional study including141cervicalsamples ofwomenattendingtheIICS,UNA. Thesampleswereprocessed by CH IIand storedwithdenaturing reagent at-80ºC.Then,theywere diluted 100 times with distilled water andsubsequently processed by PCR. HPV was detected in 51% and 43% of the samples analyzed by CH IIand PCR respectively. Seventeen of 23 positive samples by CH IIwith relatively low viral load were negative by PCR. This could be due to degradation ofthe material. In addition,sixnegative samples by CH IIwere positive by PCR suggestingthe presence of infection with HPV types not included in CH II. These results suggestthat it is possible to detect HPV by PCRfrom samples processed by CH IIprior dilution.This is a quick, easy and economic alternative which minimizes the risk of losing thegenetic material in the extraction process,and allows access to viral typing methods thatcouldprovide data aboutcirculating HPVtypesto carry out surveillance in thepost-vaccine era.

Human papillomavirus and other genital infections in indigenous women from Paraguay: a cross-sectional analytical study.

BACKGROUND: The incidence of cervical cancer in Paraguay is among the highest in the world, with the human papillomavirus (HPV) being a necessary factor for cervical cancer. Knowledge about HPV infection among indigenous women is limited. This cross-sectional study analyzed the frequency of HPV and other genital infections in indigenous Paraguayan women of the Department of Presidente Hayes. METHODS: This study included 181 sexually active women without cervical lesions. They belonged to the following ethnicities: Maká (n = 40); Nivaclé (n = 23); Sanapaná (n = 33); Enxet Sur (n = 51) and Toba-Qom (n = 34). The detection of HPV and other gynecological infectious microorganisms was performed by either molecular methods (for Mycoplasma hominis, Ureaplasma urealyticum, Chlamydia trachomatis), gram staining and/or culture (for Gardnerella vaginalis, Candida sp, Trichomonas vaginalis, Neisseria gonorrhoeae), serological methods (for Treponema pallidum, human immunodeficiency virus [HIV]) or cytology (cervical inflammation). RESULTS: A high prevalence (41.4%) of women positive for at least one sexually transmitted infection (STI) was found (23.2% any-type HPV, 11.6% T pallidum, 10.5% T vaginalis, 9.9% C trachomatis and 0.6% HIV) with 12.2% having more than one STI. HPV infection was the most frequent, with 16.1% of women positive for high-risk HPV types. There was a statistically significant association observed between any-type HPV and C trachomatis (p = 0.004), which indicates that the detection of one of these agents should suggest the presence of the other. There was no association between any-type HPV and other genital infections or cervical inflammation, suggesting that other mechanism could exist to favor infection with the virus. CONCLUSION: This multidisciplinary work suggests that STIs are frequent, making it necessary to implement control measures and improve diagnosis in order to increase the number of cases detected, especially in populations with poor access to health centers.

[Detection of high risk human papillomavirus by hybrid capture II® according cytological findings in women treated for squamous intraepithelial lesions of the cervix, period 2006/2010]. / Detección del virus del papiloma humano de alto riesgo por captura híbrida II® según hallazgos citológicos en mujeres tratadas por lesiones escamosas intraepiteliales de cuello uterino, período 2006/2010.

OBJECTIVE: To determinate the frequency of high risk human papillomavirus (HR-HPV) by hybrid capture II (r) (CH II(r)), according cytology results in women treated for squamous intraepithelial lesions of the cervix (SIL). MATERIAL AND METHODS: A descriptive cross-sectional study of a series of cases that included 122 women treated, 79 (75%) for low grade SIL (LSIL) and 43 (35%) for high grade SIL (HSIL) attending at the HPV Laboratory at the Health Sciences Research Institute (IICS), National University of Asunción (UNA), for post-treatment control during period 2006/2010. RESULTS: A total of 28% (34/122) of women treated for SIL were positive for HR-HPV, detecting viral infection in 20% of women with no SIL (NSIL) (22/108), in 83% of women with LSIL (10/12) and in 100% of women with HSIL (2/2). Of 34 women positive for HR-HPV, 10 women (29%) had high values (100 pg / mL or more) of relative viral load, detecting an increase of positive cases with severity of the lesion (28% NSIL, 30% LSIL, 50% HSIL). CONCLUSION: HR-HPV detection by CH II(r) and high relative viral load values especially in women with NSIL could help to identify treated women at risk of developing recurrence, thereby contributing to strengthening the cervical cancer prevention program.

Detección del virus del papiloma humano de alto riesgo por captura híbrida II® según hallazgos citológicos en mujeres tratadas por lesiones escamosas intraepiteliales de cuello uterino, período 2006/2010 / Detection of high risk human papillomavirus by hybrid capture II(r) according cytological findings in women treated for squamous intraepithelial lesions of the cervix, period 2006/2010

OBJETIVO: Determinar la frecuencia del virus de papiloma humano de alto riesgo oncogénico (HR-HPV) por captura híbrida II (r) (CH II(r)) según hallazgos citológicos en mujeres tratadas por lesiones escamosas intraepiteliales (SIL) de cuello uterino. MATERIAL Y MÉTODO: Estudio descriptivo de corte transverso de una serie de casos, en donde se incluyeron 122 mujeres tratadas, 79 (65%) por SIL de bajo grado (LSIL) y 43 (35%) por SIL de alto grado (HSIL) que concurrieron al Laboratorio de HPV del Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, para realizarse un control post-tratamiento, periodo 2006/2010. RESULTADOS: Se observó un total del 28% (34/122) de mujeres tratadas por SIL positivas para HR-HPV, detectándose infección viral en un 20% de las mujeres con ausencia de SIL (NSIL) (22/108), 83% de las mujeres con LSIL (10/12) y 100% de las mujeres con HSIL (2/2). De las 34 mujeres positivas para HR-HPV, 10 mujeres (29%) presentaron valores altos (100 pg/mL o más) de carga viral relativa, detectándose un aumento de casos positivos con la severidad de la lesión (28% NSIL, 30% LSIL, 50% HSIL). CONCLUSION: La detección de HR-HPV por CH II(r), así como los valores de carga viral relativa altos, en especial en mujeres con NSIL podrían ayudar a identificar mujeres tratadas con riesgo a desarrollar recidivas, contribuyendo así a fortalecer el programa de prevención de cáncer de cuello uterino. .

OBJECTIVE: To determinate the frequency of high risk human papillomavirus (HR-HPV) by hybrid capture II (r) (CH II(r)), according cytology results in women treated for squamous intraepithelial lesions of the cervix (SIL). MATERIAL AND METHODS: A descriptive cross-sectional study of a series of cases that included 122 women treated, 79 (75%) for low grade SIL (LSIL) and 43 (35%) for high grade SIL (HSIL) attending at the HPV Laboratory at the Health Sciences Research Institute (IICS), National University of Asunción (UNA), for post-treatment control during period 2006/2010. RESULTS: A total of 28% (34/122) of women treated for SIL were positive for HR-HPV, detecting viral infection in 20% of women with no SIL (NSIL) (22/108), in 83% of women with LSIL (10/12) and in 100% of women with HSIL (2/2). Of 34 women positive for HR-HPV, 10 women (29%) had high values (100 pg / mL or more) of relative viral load, detecting an increase of positive cases with severity of the lesion (28% NSIL, 30% LSIL, 50% HSIL). CONCLUSION: HR-HPV detection by CH II(r) and high relative viral load values especially in women with NSIL could help to identify treated women at risk of developing recurrence, thereby contributing to strengthening the cervical cancer prevention program. .

Reglamento del comité de ética en investigación del Instituto de Investigaciones en Ciencias de la Salud de la Universidad Nacional de Asunción (IICS-UNA) / Regulation of the committee of ethics in Investigation of the Institute of Investigations in Sciences of the Health of the National University of Asunción (IICS-UNA)

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Rare missense variants of neuronal nicotinic acetylcholine receptor altering receptor function are associated with sporadic amyotrophic lateral sclerosis.

Sporadic amyotrophic lateral sclerosis (SALS) is a motor neuron degenerative disease of unknown etiology. Current thinking on SALS is that multiple genetic and environmental factors contribute to disease liability. Since neuronal acetylcholine receptors (nAChRs) are part of the glutamatergic pathway, we searched for sequence variants in CHRNA3, CHRNA4 and CHRNB4 genes, encoding neuronal nicotinic AChR subunits, in 245 SALS patients and in 450 controls. We characterized missense variants by in vitro mutagenesis, cell transfection and electrophysiology. Sequencing the regions encoding the intracellular loop of AChRs subunits disclosed 15 missense variants (6.1%) in 14 patients compared with only six variants (1.3%) in controls (P = 0.001; OR 4.48, 95% CI 1.7-11.8). The frequency of variants in exons encoding extracellular and transmembrane domains and in intronic regions did not differ. NAChRs formed by mutant alpha3 and alpha4 and wild-type (WT) beta4 subunits exhibited altered affinity for nicotine (Nic), reduced use-dependent rundown of Nic-activated currents (I(Nic)) and reduced desensitization leading to sustained intracellular Ca(2+) concentration, in comparison with WT-nAChR. The cellular loop has a crucial importance for receptor trafficking and regulating ion channel properties. Missense variants in this domain are significantly over-represented in SALS patients and alter functional properties of nAChR in vitro, resulting in increased Ca(2+) entry into the cells. We suggest that these gain-of-function variants might contribute to disease liability in a subset of SALS because Ca(2+) signals mediate nAChR's neuromodulatory effects, including regulation of glutamate release and control of cell survival.

Detection of high risk human papillomavirus cervical infections by the hybrid capture in Asunción, Paraguay

Cervical cancer is the most frequent malignant tumour of women in Latin America being human papillomavirus (HPV) the main cause. The aim of this study was to increase the knowledge about the cervical infections with oncogenic HPV types (HR-HPV) in Asuncion, Paraguay. Two hundred and seventy-two cervical samples were analyzed using hybrid capture II assay (HCA II) for HR-HPV. The frequency of HR-HPV in the study group was 44 percent. HR-HPV was detected in 25 percent of the women negative for squamous intraepithelial lesions (NSIL), 72 percent with atypical squamous cells of undetermined significance (ASCUS), 68 percent with low SIL and 78 percent with high SIL. A moderate concordance was observed between HCA II assay and cytology (kappa: 0.43 IC95 percent 0.3 - 0.5). It was detected a high frequency of HR-HPV in women from 11 to 30 years old and in those over 60 years old. The data obtained in this study showed a high frequency of HR-HPV in woman with NSIL and ASCUS, which corroborate that the use of cytology together with HCA II assay for HR-HPV could improve remarkably the efficiency of screening programs of cervical cancer in Paraguay. Furthermore, these findings point out the need for the periodical follow-up of HR-HPV infections in older women.

Detection of high risk human papillomavirus cervical infections by the hybrid capture in Asunción, Paraguay.

Cervical cancer is the most frequent malignant tumour of women in Latin America being human papillomavirus (HPV) the main cause. The aim of this study was to increase the knowledge about the cervical infections with oncogenic HPV types (HR-HPV) in Asuncion, Paraguay. Two hundred and seventy-two cervical samples were analyzed using hybrid capture II assay (HCA II) for HR-HPV. The frequency of HR-HPV in the study group was 44%. HR-HPV was detected in 25% of the women negative for squamous intraepithelial lesions (NSIL), 72% with atypical squamous cells of undetermined significance (ASCUS), 68% with low SIL and 78% with high SIL. A moderate concordance was observed between HCA II assay and cytology (kappa: 0.43 IC(95% 0.3-0.5)). It was detected a high frequency of HR-HPV in women from 11 to 30 years old and in those over 60 years old. The data obtained in this study showed a high frequency of HR-HPV in woman with NSIL and ASCUS, which corroborate that the use of cytology together with HCA II assay for HR-HPV could improve remarkably the efficiency of screening programs of cervical cancer in Paraguay. Furthermore, these findings point out the need for the periodical follow-up of HR-HPV infections in older women.

Pathogenic point mutations in a transmembrane domain of the epsilon subunit increase the Ca2+ permeability of the human endplate ACh receptor.

The epsilon subunit of the human endplate ACh receptor (AChR) is a key determinant of the large fraction of the ACh-evoked current carried by Ca2+ ions (P(f)). Consequently, missense mutations in the epsilon subunit are potential targets for altering the P(f) of human AChR. In this paper we investigate the effects of two pathogenic point mutations in the M2 transmembrane segment AChR epsilon subunit, epsilonT264P and epsilonV259F, that cause slow-channel syndromes (SCS). When expressed in GH4C1 cells, the mutant receptors subunits raise Ca2+ permeability of the receptors approximately 1.5 and approximately 2-fold above that of wild-type, to attain P(f) values of 11.8% (epsilonT264P) and 15.4% (epsilonV259F). The latter value exceeds most P(f) values reported to date for ligand-gated ion channels. Consistent with these findings, the biionic Ca2+ permeability ratio (P(Ca)/P(Cs)) of the mutant AChRs is also increased. Upon repetitive stimulation with ACh, the mutant receptors show an enhanced current run-down compared with wild-type, leading to a strong reduction of their function. We propose that the enhanced Ca2+ permeability of the mutant receptors overrides the protective effect of desensitization and, together with the prolonged opening events of the AChR channel, is an important determinant of the excitotoxic endplate damage in the SCS.

Modulation of sensory neuron mechanotransduction by PKC- and nerve growth factor-dependent pathways.

Many sensations of pain are evoked by mechanical stimuli, and in inflammatory conditions, sensitivity to such stimuli is commonly increased. Here we used cultured sensory neurons as a model of the peripheral terminal to investigate the effects of inflammatory signaling pathways on mechanosensitive ion channels. Activation of two of these pathways enhanced transduction in a major population of nociceptors. The proinflammatory neurotrophin nerve growth factor caused an up-regulation of mechanically activated currents via a transcriptional mechanism. Activators of PKC, given in vitro and in vivo, also caused an increase in mechanically activated membrane current and behavioral sensitization to mechanical stimulation, respectively. The effect of activating PKC was inhibited by tetanus toxin, suggesting that insertion of new channels into the cell membrane is involved in sensitization. These results reveal previously undescribed mechanisms by which PKC and nerve growth factor synergistically enhance the response of nociceptors to mechanical stimuli, suggesting possible targets for pain treatment.