XML Feed for RxPG News   Add RxPG News Headlines to My Yahoo!   Javascript Syndication for RxPG News

Research Health World General
 
  Home
 
 Latest Research
 Cancer
 Psychiatry
  Depression
  Neuropsychiatry
  Personality Disorders
  Bulimia
  Anxiety
  Substance Abuse
   Alcohol
   Smoking
   Amphetamine
   Opiates
   Cannabis
   Cocaine
  Suicide
  CFS
  Psychoses
  Child Psychiatry
  Learning-Disabilities
  Psychology
  Forensic Psychiatry
  Mood Disorders
  Sleep Disorders
  Peri-Natal Psychiatry
  Psychotherapy
  Anorexia Nervosa
 Genetics
 Surgery
 Aging
 Ophthalmology
 Gynaecology
 Neurosciences
 Pharmacology
 Cardiology
 Obstetrics
 Infectious Diseases
 Respiratory Medicine
 Pathology
 Endocrinology
 Immunology
 Nephrology
 Gastroenterology
 Biotechnology
 Radiology
 Dermatology
 Microbiology
 Haematology
 Dental
 ENT
 Environment
 Embryology
 Orthopedics
 Metabolism
 Anaethesia
 Paediatrics
 Public Health
 Urology
 Musculoskeletal
 Clinical Trials
 Physiology
 Biochemistry
 Cytology
 Traumatology
 Rheumatology
 
 Medical News
 Health
 Opinion
 Healthcare
 Professionals
 Launch
 Awards & Prizes
 
 Careers
 Medical
 Nursing
 Dental
 
 Special Topics
 Euthanasia
 Ethics
 Evolution
 Odd Medical News
 Feature
 
 World News
 Tsunami
 Epidemics
 Climate
 Business
 
 India
Search

Last Updated: Nov 18, 2006 - 12:32:53 PM
Systematic Review
Alcoholism: Clinical & Experimental Research

Alcohol Channel
subscribe to Alcohol newsletter

Latest Research : Psychiatry : Substance Abuse : Alcohol

   DISCUSS   |   EMAIL   |   PRINT
Chronobiological disruptions in human alcoholics - Review Study
Aug 15, 2005 - 5:53:00 PM, Reviewed by: Dr.

"Alcohol can directly alter the molecular clock machinery in different cell types, such as neuroendocrine cells and immune cells, and the molecular components of the central clock in the hypothalamus that coordinates the circadian rhythms in physiology and behavior," said Sarkar

 
Circadian rhythms refer to biological phenomena that oscillate within a 24-hour cycle, in keeping with the earth's rotation. A review in the August issue of Alcoholism: Clinical & Experimental Research summarizes new findings on interactions between alcohol and the "clock genes" that underlie circadian rhythmicity.

"The human body, like many other mammals and some bacteria, displays changes in functions and behavior that wax and wane through the cycle of day and night," said Dipak K. Sarkar, director of the endocrinology program and biomedical division of the Center of Alcohol Studies at Rutgers University, and corresponding author for the study. "These rhythms are not simply a response to 24-hour changes in the physical environment but instead arise from a timekeeping system or 'biological clock' within the body. An individual has more than 100 circadian rhythms that are unique and influence various aspects of body functions, including heart rate, blood pressure, body temperature, hormone levels, pain threshold and even the ability to fight against harmful invaders like bacteria and virus. Almost no area of our body is unaffected by these rhythms."

"This review shows that alcohol exposure can alter biological rhythmicity and, as a result, have deleterious consequences on a number of important physiological systems," noted Robert J. Handa, professor of neuroscience at Colorado State University. "The fact that alcohol intake may influence the molecular underpinnings of circadian rhythmicity is an emerging concept with potentially important biomedical ramifications. Although a majority of these studies have been performed in rodent models � observations of humans correlate with the animal studies and imply that similar types of pathology are associated with alcohol intake."

Some of the review's key findings were:

# The chronobiological disruptions observed in human alcoholics appear to be partially due to alcohol-induced disruption of fundamental biological timing processes, and partially due to genetic associations.

"Generally speaking," said Handa, "fluctuations in physiological function are synchronized to the 24-hour day by a 'master' clock which resides within the suprachiasmatic nucleus (SCN) of the brain's hypothalamus. The SCN collects temporal information from the retina and elsewhere, passing it to various physiological systems of the body. By disrupting the ability of the 'master clock' to synchronize physiological systems across the 24-hour day, or by rendering individual physiological systems unable to respond to the signals of the master clock, alcohol intake may result in what could be considered 'physiological anarchy.' The pathology resulting from such generalized disorder could be widespread."

Handa added that it is still unknown whether the genetics underlying alcohol preference drives the circadian dysregulation, or whether the genetics of circadian dysregulation is what drives alcohol preference. "Presumably it is the latter," he said. "In animals where there is a genetic predisposition to weakened circadian rhythmicity, the stress associated with the absence of physiological order results in alcohol preference. This could also be the case in some human conditions, such as Seasonal Affective Disorder."

Sarkar concurred. "Alcohol-preferring rats have an altered light response in their central clock, and alcoholic humans have abnormality in the expression of Period genes that regulate the biological clock," he said. "We cannot say that people are genetically predisposed to drinking through their circadian rhythmicity, but one could interpret the data to mean that if an individual's biological clock does not function properly, they may have increased motivation to consume more alcohol."

# Chronic alcohol administration appears to significantly alter central and internal clocks that govern neuroendocrine functions.

"Both 'central clocks' in the SCN, and 'internal clocks' in many neuroendocrine and other cells, depend on the coordinated expression of specific 'clock genes,'" said Sarkar. "Animal models have shown us that chronic alcohol drinking hampers the daily expression of these clock genes, which can disrupt the circadian release of neuroendocrine hormones that govern stress reactivity, food intake and various other body functions."

# Alcohol consumption may influence immune function by altering an individual's central and internal clock activities.

"It is well known that immune function can be influenced by stress hormones and that stress hormones undergo daily rhythmic fluctuations," said Handa. "As a result, immune function possesses a circadian component. A new twist on this story, however, is that the immune system is not just a passive partner responding to circadian signals, but possesses an intrinsic clock of its own that is synchronized to an individual's central clock via hormonal and autonomic signals."

# There may be a molecular basis for greater alcohol consumption among shift workers and people suffering from jet lag.

"In both cases," said Handa, "the activity of the individual and the physiological requirements for such activity are at odds with the regulatory timing cues provided by the SCN. For example, in the case of the individual working the late shift, light signals providing synchronizing information to the SCN are normal, yet the individual is active during a period when physiological rhythms are normally set for rest. Such activity resets peripheral rhythms away from that of the master clock and disorder ensues until activity rhythms are realigned with that of the SCN."

# Alcohol may interact with different human physiological systems that are subject to circadian rhythmicity.

"Alcohol can directly alter the molecular clock machinery in different cell types, such as neuroendocrine cells and immune cells, and the molecular components of the central clock in the hypothalamus that coordinates the circadian rhythms in physiology and behavior," said Sarkar. "In addition, chronic alcohol consumption may also affect the synchronizing signals by which clocks in different tissues talk to each other."

In summary, said Sarkar, new discoveries in the emerging field of Chronobiology of Alcohol Abuse indicate that alcohol consumption has long-term adverse effects on the body's internal clocks, that altered circadian rhythm due to rotating shift work and traveling over time zones may increase the propensity of alcohol-drinking behavior, and that chronic drinking may increase the risk for sleep disturbances, depression, compromised immune function, and increased incidence of certain forms of cancers.

"We are now conducting studies using laboratory animals to understand how alcohol drinking in the adult alters the molecular machinery governing the body's biological clock," said Sarkar. "We are also determining the negative health consequences of maternal alcohol abuse on the offspring's circadian neuroendocrine and immune system functions."
 

- August issue of Alcoholism: Clinical & Experimental Research
 

Alcoholism: Clinical & Experimental Research

 
Subscribe to Alcohol Newsletter
E-mail Address:

 

Alcoholism: Clinical & Experimental Research (ACER) is the official journal of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism. Co-authors of the ACER paper, "Alcohol Consumption and the Body's Biological Clock," were: Rainer Spanagel of the Department of Psychopharmacology at the Central Institute of Mental Health in Germany; Alan M. Rosenwasser of the Department of Psychology at the University of Maine; and Gunter Schumann of the Department of Psychiatry and Psychotherapy, and the Department of Addictive Behaviour and Addiction Medicine, at the Central Institute of Mental Health in Germany. The review was funded by the National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism, and several European research funding agencies.

Related Alcohol News

DNA highly-promising predictor for successful treatment of alcoholics
Nicotine may actually reduce blood alcohol concentrations
Alcoholics' deficits in smell are linked to frontal lobe dysfunction
Asp carriers of the OPRM1 gene taking naltrexone have increased urge to drink
Early Drinking Linked to Risk of Alcohol Dependence
Inattentional blindness more likely under influence of alcohol
Moderate alcohol intake associated with better mental function
Medical management with naltrexone or behavioral therapy can effectively treat alcohol dependence
Underage drinkers account for about 17 percent of consumer expenditures for alcohol
Alcohol could make you more depressed: study


For any corrections of factual information, to contact the editors or to send any medical news or health news press releases, use feedback form

Top of Page

 

© Copyright 2004 onwards by RxPG Medical Solutions Private Limited
Contact Us