Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “FIRES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources

A clinician's guide to surgical fires. How they occur, how to prevent them, how to put them out.

Surgical fires--fires that occur on or in a surgical patient--are a rare but devastating complication of surgical procedures. They can happen during almost any kind of operation and can have dire consequences for both the patient and the hospital. The risk of surgical fires can be minimized as long as everyone on the surgical team understands how fires start and what to do when they occur. It's important to recognize the interaction among ignition sources, oxidizers, and fuels--the three sides of the classic fire triangle. What's more, staff members need to be alert to "hidden" fire risks, such as unsuspected oxygen-enriched atmospheres and less-than-obvious fuels. They also need to be drilled in the correct steps for responding to fires. In this guide, we describe the elements of surgical fires, including the types of equipment and materials that make up each side of the fire triangle. Through a series of case histories, we illustrate the many ways in which fires can start in the operating room. We also provide a detailed list of prevention methods. Finally, we describe the steps to take and the equipment to use--and not use--when a fire does occur.

Electrosurgery↗

Evaluated community fire safety interventions in the United States: a review of current literature.

The purpose of the study was to assess the state of fire prevention research, provide an updated synthesis of evaluated fire prevention programs, and discuss the role of fire fighters and data systems in prevention efforts. The review included all evaluations of U.S. based fire prevention interventions published between January 1998 and September 2004 and any earlier articles about U.S. fire prevention interventions not included in two prior review articles. We retrieved information from each identified study including evaluation findings, involvement of fire service personnel and use of existing data systems. We identified twelve articles: seven reported on smoke alarm interventions, three on multi-faceted programs, and two other programs. Five programs involved fire service personnel in the design, implementation, and/or evaluation, and three used existing data systems. Studies reviewed suggest that canvassing and smoke alarm installations are the most effective means of distributing alarms and increasing the functional status of distributed alarms. The functionality of smoke alarms, an issue noted in earlier reviews, remains a problem. Programs involving partnerships with fire departments have indicated success in preventing fires and deaths, improving smoke alarm ownership and functional status, and improving children's fire safety knowledge. Using existing data systems to target and to evaluate interventions was effective. In the years since prior reviews, some improvements in the rigor of evaluation designs have been made, but there is still a need for high quality evaluations that will inform fire injury prevention efforts.

Community-Institutional Relations↗

Ames test: mutagenic activity of airborne particles collected on airconditioner filters during the fire at a Sandoz storehouse in Schweizerhalle on November 1, 1986.

The mutagenic activity of methanol extracts from airconditioner filters was tested using the standard plate-incorporation procedure for the Ames test and the strains Salmonella typhimurium TA97, TA98 and TA100 as test organisms. In a first set of experiments filters from 4 buildings were investigated. For each building the mutagenic activity of a filter which was in use during the fire (fire-exposed) was compared with the mutagenic activity of a filter which was exposed for a similar time span to normal urban air (non-exposed). While for 1 pair of filters the non-exposed extract was more mutagenic than the fire-exposed material, the opposite was found for 2 other filter pairs, and in 1 case there was hardly any difference in the mutagenic activities of the fire-exposed and the non-exposed filter extracts. Overall differences by factors up to 100 were observed in the mutants/m3 air values of the most and the least mutagenic filter extracts. The second group of experiments was performed to investigate the variations in mutagenic activity of filter extracts occurring due to changes in the weather conditions. Airborne particles were collected for 3 consecutive periods of 10-11 days at the 2 buildings where the extracts of the fire-exposed filters had been found to be more mutagenic than the corresponding control materials. The differences between the strongest and the weakest mutagenic filter extracts of these series were similar to the differences observed previously between the fire-exposed filters and the non-exposed filter materials. The highest mutagenic activities found in the second group of experiments was similar, at both sites, to the mutagenic activities measured in the fire-exposed extracts from these 2 buildings. Since the differences in the mutagenic activities of filters exposed to urban air during the different meteorological conditions were similar to the differences observed between fire-exposed and non-exposed materials, it is not possible to state whether the fire led to the distribution of mutagenic chemicals, although it is theoretically possible. However, based on the observation that the maximal mutagenic activities of the fire-exposed and the non-exposed extracts were similar, the present study allows the conclusion that the mutagenic burden for the population of the area of Basel was not significantly increased by the fire in Schweizerhalle on November 1, 1986.

Air Pollutants↗

Regulatory aspects of fire toxicology.

Fire creates a complex toxic environment involving flame, heat, oxygen depletion, smoke, and toxic gases. The nature of that environment is dependent upon not only the materials present but on the fire event, that is, the fire scenario. Materials have different toxic gas profiles under different conditions; therefore, toxic fire gas generation is not intrinsic to any one material. Large fires in buildings constitute a severe toxic threat regardless of the materials being burned. In the past, building codes in the United States included the phrase, "no more toxic than wood," in reference to fire gases from building materials. Such phrases have recently been deleted, because of the lack of either an accepted definition or test methodology to assess toxicity. While several states have attempted regulatory activity, the most recent approach (taken by the state of New York) has been the establishment of a data bank on toxic potency of building and furnishing materials. The utility of such a data bank without available hazard analysis methodology is open to discussion, since toxic potency data are not directly applicable to toxic hazard assessment. A number of small-scale animal exposure tests have been developed to assess the potency of the toxic combustion products from combustible materials. Criticism of these tests relates to the relevance of the combustion module (a smoke generation apparatus) and the appropriateness of the animal model, particularly for irritant gases. Recent data from more than 2000 fire fatality cases and carbon monoxide exposure cases are discussed in this paper to help put small-scale laboratory test results into perspective. Toxicity is only one of the several fire properties related to materials. All fire parameters are interrelated, that is, they are not independent variables. Thus, predicting the toxicity of burning materials is a problem without a comprehensive solution. Measures have been taken, however, to reduce the number of fires and to reduce fire severity.

Animals↗

Effects of anthropogenic fire history on savanna vegetation in northeastern Namibia.

Anthropogenic fires in Africa are an ancient form of environmental disturbance, which probably have shaped the savanna vegetation more than any other human induced disturbance. Despite anthropogenic fires having played a significant role in savanna management by herders, previous ecological research did not incorporate the traditional knowledge of anthropogenic fire history. This paper integrates ecological data and anthropogenic fire history, as reconstructed by herders, to assess landscape and regional level vegetation change in northeastern Namibia. We investigated effects of fire frequency (i.e. <5, 5-10 and >10 years) to understand changes in vegetation cover, life form species richness and savanna conditions (defined as a ratio of shrub cover to herbaceous cover). Additionally, we analysed trends in the vegetation variables between different fire histories at the landscape and regional scales. Shrub cover was negatively correlated to herbaceous cover and herbaceous species richness. The findings showed that bush cover homogenisation at landscape and regional scales may suggest that the problem of bush encroachment was widespread. Frequent fires reduced shrub cover temporarily and promoted herbaceous cover. The effects on tree cover were less dramatic. The response to fire history was scale-independent for shrub, herbaceous and tree cover, but scale-dependent for the richness of grass and tree life forms. Fire history, and not grazing pressure, improved savanna conditions. The findings emphasise the need to assess effects of anthropogenic fires on vegetation change before introducing new fire management policies in savanna ecosystems of northeastern Namibia.

Ecology↗

Deaths and injuries from house fires.

BACKGROUND: We sought to define the factors associated with house fires and related injuries by analyzing the data from population-based surveillance. METHODS: For 1991 through 1997, we linked the following data for Dallas: records from the fire department of all house fires (excluding fires in apartments and mobile homes), records of patients transported by ambulance, hospital admissions, and reports from the medical examiner of fatal injuries. RESULTS: There were 223 injuries (91 fatal and 132 nonfatal) from 7190 house fires, for a rate of 5.2 injured persons per 100,000 population per year. Rates of injury related to house fires were highest among blacks (relative risk, 2.8; 95 percent confidence interval, 2.1 to 3.6) and in people 65 years of age or older (relative risk, 2.6; 95 percent confidence interval, 1.9 to 3.5). Census tracts with low median incomes had the highest rates of injury related to house fires (relative risk as compared with census tracts with high median incomes, 8.1; 95 percent confidence interval, 2.5 to 32.0). The rate of injuries was higher for fires that began in bedrooms or living areas (relative risk, 3.7); that were started by heating equipment, smoking, or children playing with fire (relative risk, 2.6); or that occurred in houses built before 1980 (relative risk, 6.6). Injuries occurred more often in houses without functioning smoke detectors (relative risk, 1.5; 95 percent confidence interval, 1.0 to 2.4). The prevalence of functioning smoke detectors was lowest in houses in the census tracts with the lowest median incomes (P<0.001). CONCLUSIONS: Rates of injuries related to house fires are highest in elderly, minority, and low-income populations and in houses without functioning smoke detectors. Efforts to prevent injuries and deaths from house fires should target these populations.

Adolescent↗

Characterization of firefighter exposures during fire overhaul.

Previous studies have characterized firefighter exposures during fire suppression. However, minimal information is available regarding firefighter exposures during overhaul, when firefighters look for hidden fire inside attics, ceilings, and walls, often without respiratory protection. A comprehensive air monitoring study was conducted to characterize City of Phoenix firefighter exposures during the overhaul phase of 25 structure fires. Personal samples were collected for aldehydes; benzene; toluene; ethyl benzene; xylene; hydrochloric acid; polynuclear aromatic hydrocarbons (PNA); respirable dust; and hydrogen cyanide (HCN). Gas analyzers were employed to continuously monitor carbon monoxide (CO), HCN, nitrogen dioxide (NO2), and sulfur dioxide (SO2). Area samples were collected for asbestos, metals (Cd, Cr, Pb), and total dust. During overhaul the following exceeded published ceiling values: acrolein (American Conference of Governmental Industrial Hygienists [ACGIH] 0.1 ppm) at 1 fire; CO (National Institute for Occupational Safety and Health [NIOSH] 200 ppm) at 5 fires; formaldehyde (NIOSH 0.1 ppm) at 22 fires; and glutaraldehyde (ACGIH 0.05 ppm) at 5 fires. In addition, the following exceeded published short-term exposure limit values: benzene (NIOSH 1 ppm) at two fires, NO2 (NIOSH 1 ppm) at two fires, and SO2 (ACGIH 5 ppm) at five fires. On an additive effects basis, PNA concentrations exceeded the NIOSH recommended exposure limits (0.1 mg/M3) for coal tar pitch volatiles at two fires. Maximum concentrations of other sampled substances were below their respective permissible exposure limits. Initial 10-min average CO concentrations did not predict concentrations of other products of combustion. The results indicate that firefighters should use respiratory protection during overhaul. In addition, these findings suggest that CO should not be used as an indicator gas for other contaminants found in this atmosphere.

Air Pollutants, Occupational↗

Long-term effects of fire frequency on carbon storage and productivity of boreal forests: a modeling study.

Climate change is predicted to shorten the fire interval in boreal forests. Many studies have recorded positive effects of fire on forest growth over a few decades, but few have modeled the long-term effects of the loss of carbon and nitrogen to the atmosphere. We used a process-based, dynamic, forest ecosystem model, which couples the carbon, nitrogen and water cycles, to simulate the effects of fire frequency on coniferous forests in the climate of Prince Albert, Saskatchewan. The model was calibrated to simulate observed forest properties. The model predicted rapid short-term recovery of net primary productivity (NPP) after fire, but in the long term, supported the hypotheses that (1) current NPP and carbon content of boreal forests are lower than they would be without periodic fire, and (2) any increase in fire frequency in the future will tend to lower NPP and carbon storage. Lower long-term NPP and carbon storage were attributable to (1) loss of carbon on combustion, equal to about 20% of NPP over a 100-200 year fire cycle, (2) loss of nitrogen by volatilization in fire, equal to about 3-4 kg N ha(-1) year(-1) over a 100-200 year fire cycle, and (3) the fact that the normal fire cycle is much shorter than the time taken for the forest (especially the soil) to reach an equilibrium carbon and nitrogen content. It was estimated that a shift in fire frequency from 200 to 100 years over 1000 Mha of boreal forest would release an average of about 0.1 Gt C year(-1) over many centuries.

Carbon↗

The epidemiology of fire-related deaths in Alabama, 1992-1997.

The state of Alabama has one of the highest fire-related fatality rates in the nation. The goal of this study was to present the epidemiology of fire-related deaths in the state of Alabama. Fatality reports for all fire-related deaths in the state of Alabama from 1992 to 1997 were obtained from the State Fire Marshall's Office. Fatality rates were calculated and compared according to age, sex, and race. Descriptive statistics were generated for population and fire characteristics. Fatality rates were higher among black people, men, children, and older people. Approximately half (48.8%) of the deaths occurred between the months of November and March; July had the lowest proportion of deaths (5.0%). Residential fires accounted for the largest proportion of deaths. Fatality rates were higher for mobile home residents. Overall, smoke detectors were present in only 32.5% of the residential fires. The presence of smoke detectors was more common with deaths in urban locations (41.8%) than with deaths in rural locations (20.8%). The most frequently reported cause of fatal fires was misuse of cigarettes. More than half of the victims aged 18 years and older tested positive for alcohol. Fire prevention efforts should focus on smoke detectors, fire-safe cigarettes, and alcohol. Mobile home residents should also be targeted for fire prevention initiatives.

Accident Prevention↗

Income, housing, and fire injuries: a census tract analysis.

OBJECTIVES: This study investigates the social and demographic correlates of nonfatal structural fire injury rates for the civilian population for Philadelphia census tracts during 1993-2001. METHODS: The author analyzed 1,563 fire injuries by census tract using the 1990 census (STF 3) and unpublished data from the Office of the Fire Marshal of the Philadelphia Fire Department. Injury rates were calculated per 1,000 residents of a given census tract. Multiple regression was used to determine significant variables in predicting fire injuries in a given census tract over a nine-year period and interaction effects between two of these variables-age of housing and income. RESULTS: Multiple regression analysis indicates that older housing (prior to 1940), low income, the prevalence of vacant houses, and the ability to speak English have significant independent effects on fire injury rates in Philadelphia. In addition, the results show a significant interaction between older housing and low income. CONCLUSIONS: Given the finding of very high rates of fire injuries in census tracts that are both low income and have older housing, fire prevention units can take preventative measures. Fire protection devices, especially smoke alarms, should be distributed in the neighborhoods most at risk. Multiple occupancy dwellings should have sprinkler systems and fire extinguishers. Laws concerning the maintenance of older rental housing need to be strictly enforced. Vacant houses should be effectively boarded up or renovated for residential use. Fire prevention material should be distributed in a number of languages to meet local needs.

Burns↗

Mortality and life expectancy of professional fire fighters in Hamburg, Germany: a cohort study 1950-2000.

BACKGROUND: The healthy worker effect may hide adverse health effects in hazardous jobs, especially those where physical fitness is required. Fire fighters may serve as a good example because they sometimes are severely exposed to hazardous substances while on the other hand their physical fitness and their strong health surveillance by far exceeds that of comparable persons from the general population. METHODS: To study this effect a historic cohort study was conducted to assess mortality and life expectancy of professional fire fighters of the City of Hamburg, Germany. Fire departments and trade unions questioned the validity of existing studies from outside Germany because of specific differences in the professional career. No mortality study had been conducted so far in Germany and only few in Europe. Information on all active and retired fire fighters was extracted from personnel records. To assure completeness of data the cohort was restricted to all fire fighters being active on January 1, 1950 or later. Follow up of the cohort ended on June 30th 2000. Vital status was assessed by personnel records, pension fund records and the German residence registries. Mortality of fire fighters was compared to mortality of the Hamburg and German male population by means of standardized mortality ratios. Life expectancy was calculated using life table analysis. Multivariate proportional hazard models were used to assess the effect of seniority, time from first employment, and other occupational characteristics on mortality. RESULTS: The cohort consists of 4640 fire fighters accumulating 111,796 person years. Vital status could be determined for 98.2% of the cohort. By the end of follow up 1052 person were deceased. Standardized Mortality Ratio (SMR) for the total cohort was 0.79 (95% CI, 0.74-0.84) compared to Hamburg reference data and 0.78 (95% CI, 0.74-0.83) compared to National German reference data. Conditional life expectancy of a 30 year old fire fighter was 45.3 years as compared to 42.9 year of a German male in normal population. Job tasks, rank status and early retirement negatively influenced mortality. For fire fighters with comparably short duration of employment the mortality advantage diminished with longer time since first employment. SMR of persons who retired early was 1.25 (95% CI, 1.13-1.60) in reference to the general German population and the SMR of 1.71 (1.18-2.50) in the multivariate regression model. CONCLUSION: A strong healthy worker effect was observed for the cohort, which diminished with longer time since first employment for fire fighters with shorter duration of employment, as expected. The negative effects on mortality of job tasks, rank status and in particular early retirement indicate the presence of undetermined and specific risks related to occupational hazards of fire fighters.

Adolescent↗

Educational videos on surgical fires.

One of the most frightening events for any surgical staff member, and one of the most devastating events for any surgical patient, is a fire that occurs on or in the patient during a procedure. Surgical fires, as these are called, are fortunately very rare--but they do occur. ECRI has been investigating, reporting on, and teaching about surgical fires for nearly 30 years. Our experience has shown that most of these fires could have been avoided had the staff been adequately educated about the hazards. Educational videos are just one tool that hospitals can use to provide the fire-safety training that surgical staff require. In this Evaluation, we look at five videos covering fire safety in the operating room (OR). Our examination focuses on how well these videos address surgical fires in particular, since these can be the most devastating type of OR fire. We rate each video on how effectively it meets the fire-safety training needs of today's healthcare workers. The videos run the gamut from excellent to unsafe. We rate one Preferred because it contains particularly detailed information, and we rate another Acceptable because it provides good information overall. Two other videos are Not Recommended--the information in one of them, while good, is incomplete, and the other focuses too broadly on OR fires, with not enough emphasis on surgical fires. The fifth video provides two dangerous recommendations and is therefore Unacceptable.

Fires↗

[GIS-based forest fire risk zone mapping in Daxing'an Mountains].

In this study, the Yuying and Fendou forest farms of Tuqiang Forest Bureau in Daxing'an Mountains were chosen as test areas, and their vegetation type, altitude, slop, aspect, and settlement buffer were selected as the main forest fire factors. The circumstances of forest fire risk were quantified by the factor-weights union method with the support of GIS. Four classes of forest fire risk ranging from low to extreme were generated. The none-, low, moderate, high, and extremely high fire risk zones accounted for 0.37%, 0.63%, 38.67%, 58.63% and 1.70%, respectively, which was in corresponding with normal distribution. About 60.33% of the test areas were predicted to be upper moderate risk zones, indicating that the forest fire management task in these areas is super onerous. There was an obvious regional difference in the distribution of forest fire risk zones, being higher in the center and lower around the center, and the difference in fire factors was also obvious. The GIS-based forest fire risk model of test areas strongly cohered with the actual fire-affected sites in 1987, which suggested that the forest fire risk zone mapping had a higher reliability, and could be used as the reference and guidance of forest fire management.

China↗

Fire-related deaths among Aboriginal people in British Columbia, 1991-2001.

BACKGROUND: Fire-related mortality rates are known to be higher in Aboriginal people in BC. The purpose of this study was to describe the epidemiology and context of fire-related deaths in this population. METHODS: All death registrations attributable to fires in the province were identified by the B.C. Vital Statistics Agency (1991-2001). Age-specific death rates (ASDR) and age-standardized mortality rates (ASMR) were calculated for Status Indians and other residents. Data from Coroner's reports from the B.C. Coroners' Service (1997-2001) were used to describe the context of Aboriginal fire-related deaths. RESULTS: The overall fire-related ASMR for Status Indians and other residents were 0.66 deaths and 0.07 deaths/10,000 population respectively. Annual ASMR for both populations were constant over the study period. ASDR were higher in every age category for Status Indians; children and seniors had higher rates in both populations. Twenty-seven Aboriginal fatalities (20 fires) were identified for the contextual analysis. Key findings were: 48% of the total sample had elevated blood alcohol levels; 30% of the fires were caused by lit cigarettes (majority of decedents were intoxicated); 15% of the fires were caused by electric heating sources; at least 34% of fires occurred in homes with absent or non-functional smoke alarms. INTERPRETATION: Fire-related mortality among Aboriginal people in BC is a preventable public health concern. In this population, fire safety and prevention programs should consider improving the prevalence of functioning smoke alarms, promoting the safe use of heat sources, and decreasing smoking behaviours and the use of alcohol.

Accident Prevention↗

Unintentional house fire deaths in Alberta 1985-1990: a population study.

We extracted data from the Medical Examiner's files for all fire deaths in Alberta reported to the Medical Examiner's for the period 1985-1990. Of the 320 fire deaths, 183 (57%) were unintentional deaths from house fires. The highest house fire death rates occurred in children 0-4 years and in adults > or = 80 years of age (2.9 and 3.2 per 100,000 per year). The majority (53%) of fatal house fires occurred in single detached dwellings but the rate of fatal house fires was 9.0 times higher in moveable dwellings than in single detached dwellings. At least 61 (33%) of unintentional fatal house fires were caused by smokers' material. Blood alcohol levels above 0.8 g/L were found in 84 (59%) of victims tested and in 39 (76%) of victims of fires caused by smoking materials. 143 (78%) house fire deaths were due, at least in part, to inhalation of toxic fumes. The cause of fatal house fires in Alberta is multifactorial. However, particular attention should be paid towards the lethal combination of cigarettes and alcohol in preventing these fires.

Accidents, Home↗

Experience-dependent modifications of hippocampal place cell firing.

Understanding the empirical rules that regulate alterations of hippocampal firing fields will enhance our understanding of hippocampal function. The current study sought to extend previous research in this area by examining the effect of substituting a new stimulus for a familiar stimulus in a familiar environment. Hippocampal place cells were recorded while rats chased food pellets scattered onto the floor of a cylindrical apparatus with a white cue card affixed to the apparatus wall. Once a place cell had been recorded in the presence of the white card, the white card was replaced by a black card of the same size and shape. The place cell was then recorded in the presence of the black card. Thirty-six cells were recorded using this procedure. All cells had stable firing fields in the presence of the white card. Both the white and black cards had stimulus control over place cell firing; generally, rotation of either card caused an equal rotation of the firing fields present. When the black card was substituted for the white card, place cells showed time-variant changes in their spatial firing patterns. The change was such that the spatial firing patterns of the majority of place cells were similar in the presence of the white and black cards during initial black card exposures. During subsequent presentations of the black card, the spatial firing patterns associated with the 2 cards became distinct from each other. Once the differentiation of firing patterns had occurred in a given rat, all place cells subsequently recorded from that rat had different firing patterns in the presence of the white and black cards. The findings are discussed relative to sensory-, motor-, attentional-, and learning-related interpretations of hippocampal function. It is argued that the time-variant alteration of place cell firing fields observed following exposure to a novel stimulus in this study reflects an experience-dependent modification of place cell firing patterns.

Animals↗

Firing relations of medial septal neurons to the hippocampal theta rhythm in urethane anesthetized rats.

On the basis of spontaneous firing patterns and relations to the hippocampal theta rhythm, three cell types were identified within the medial septal nucleus and vertical limb of the nucleus of the diagonal band of Broca (MSN-NDB). In addition to the well known rhythmically bursting cells that fired in bursts on each cycle of the hippocampal theta rhythm, two other cell types are distinguished. "Clock" cells fired at high rates with a very regular, periodic firing pattern that was unrelated to the theta rhythm. "Irregular" cells fired at much lower rates, especially during theta rhythm, and had a pseudo-random firing pattern. The firing of "irregular" cells was often significantly phase-locked to the hippocampal theta rhythm. Crude estimates of the relative proportions of these cell types suggest that the rhythmically bursting cells comprise about 75% of the cells of the MSN-NDB. These three cell types bear a remarkable resemblance, in firing patterns and relative proportions, to the three principal cell types of the medial septal nuclei described in the freely moving rat (Ranck 1976). Measurements of the preferred phases of firing of 128 rhythmically bursting septal neurons (including 22 atropine-resistant and 11 atropine-sensitive cells) indicate that there is no single preferred phase of firing for the population. Rather the distribution of phases over the theta cycle is statistically flat. Variations in recording locations cannot account for this distribution since large differences in preferred phase were found for pairs of cells at the same location. Similarly, plotting only the group of cells identified as projection cells by antidromic activation from the fimbria/fornix, failed to reveal a peak in the distribution. In contrast to the rhythmically bursting cells, the distribution of preferred firing phases for the "irregular" cells with a significant phase-locking to the theta rhythm did have a clear peak. The peak occurred near the dentate theta rhythm positivity, consistent with the hypothesis that they are driven by feedback from CA1 complex-spike cells.

Action Potentials↗

GABA(B) receptor-mediated modulation of the firing pattern of ventral tegmental area dopamine neurons in vivo.

Previous work demonstrates the fundamental role of the firing pattern, specifically the burst firing mode of midbrain dopamine (DA) neurons in the regulation of DA release. Spontaneous burst firing has been shown to be dependent upon NMDA receptor activation of the DA cells. In addition to NMDA receptors, previous studies have reported that also GABA(B) receptors modulate the firing pattern of DA neurons in the substantia nigra. In the present electrophysiological study the role of GABA(B) receptors in the modulation of the firing pattern of DA neurons in the ventral tegmental area (VTA) in anaesthetised Sprague-Dawley rats was analysed. Systemic administration of the selective and potent GABA(B) receptor agonist baclofen dose-dependently reduced firing rate and burst firing in VTA DA neurons. An increase in the regularity of DA cell firing was also observed. All these effects were effectively antagonized by administration of the selective GABA(B) antagonist CGP 35348 (100 mg/kg or 200 mg/kg, i.v.). Administration of CGP 35348 (400 mg/kg, i.v.) per se was associated with a long-lasting increase in burst firing activity. The effects of systemic administration of baclofen, alone or in combination with CGP 35348, on the firing rate were largely mimicked by local microiontophoretic application of the drugs onto the DA neurons.Our findings indicate that central GABA(B) receptors may contribute to control of the burst firing mode of VTA DA neurons. Physiologically, activation of GABA(B) receptors may subserve a dampening function on VTA DA cell excitability which may counterbalance NMDA receptor-mediated excitation.

Action Potentials↗