Limits...
Neuroadaptation in nicotine addiction: update on the sensitization-homeostasis model.

DiFranza JR, Huang W, King J - Brain Sci (2012)

Bottom Line: One such theory, the sensitization-homeostasis (SH) model, postulates that nicotine suppresses craving circuits, and this triggers the development of homeostatic adaptations that autonomously support craving.Over the past decade, many controversial aspects of the SH model have become well established by the literature, while some details have been disproven.We conclude by outlining directions for future research based on the updated model, and commenting on how new experimental studies can gain from the framework put forth in the SH model.

View Article: PubMed Central - PubMed

Affiliation: Department of Family Medicine and Community Health, University of Massachusetts Medical School, 55 Lake Avenue, Worcester, MA 01655, USA. difranzj@ummhc.org.

ABSTRACT
The role of neuronal plasticity in supporting the addictive state has generated much research and some conceptual theories. One such theory, the sensitization-homeostasis (SH) model, postulates that nicotine suppresses craving circuits, and this triggers the development of homeostatic adaptations that autonomously support craving. Based on clinical studies, the SH model predicts the existence of three distinct forms of neuroplasticity that are responsible for withdrawal, tolerance and the resolution of withdrawal. Over the past decade, many controversial aspects of the SH model have become well established by the literature, while some details have been disproven. Here we update the model based on new studies showing that nicotine dependence develops through a set sequence of symptoms in all smokers, and that the latency to withdrawal, the time it takes for withdrawal symptoms to appear during abstinence, is initially very long but shortens by several orders of magnitude over time. We conclude by outlining directions for future research based on the updated model, and commenting on how new experimental studies can gain from the framework put forth in the SH model.

No MeSH data available.


Related in: MedlinePlus

When the down-stream effects of nicotine wear off, the Withdrawal-Related Adaptations (WRA) continue to stimulate the Craving Generation System (CGS) resulting in the spontaneous generation of craving in the absence of smoking cues. This prompts the smoker to smoke every time the effect of nicotine wears off.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4061804&req=5

brainsci-02-00523-f004: When the down-stream effects of nicotine wear off, the Withdrawal-Related Adaptations (WRA) continue to stimulate the Craving Generation System (CGS) resulting in the spontaneous generation of craving in the absence of smoking cues. This prompts the smoker to smoke every time the effect of nicotine wears off.

Mentions: 4. When the indirect inhibitory effect of nicotine wears off, the stimulatory withdrawal-related adaptations activate the Craving Generation System. This causes the addicted smoker to experience withdrawal-induced craving for nicotine whenever the effect of nicotine wears off (Figure 4). In novice smokers, it may take several weeks for the down-stream effects of nicotine to wear off, and consequently the latency from the last cigarette to the onset of withdrawal-related craving may be several weeks.


Neuroadaptation in nicotine addiction: update on the sensitization-homeostasis model.

DiFranza JR, Huang W, King J - Brain Sci (2012)

When the down-stream effects of nicotine wear off, the Withdrawal-Related Adaptations (WRA) continue to stimulate the Craving Generation System (CGS) resulting in the spontaneous generation of craving in the absence of smoking cues. This prompts the smoker to smoke every time the effect of nicotine wears off.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061804&req=5

brainsci-02-00523-f004: When the down-stream effects of nicotine wear off, the Withdrawal-Related Adaptations (WRA) continue to stimulate the Craving Generation System (CGS) resulting in the spontaneous generation of craving in the absence of smoking cues. This prompts the smoker to smoke every time the effect of nicotine wears off.
Mentions: 4. When the indirect inhibitory effect of nicotine wears off, the stimulatory withdrawal-related adaptations activate the Craving Generation System. This causes the addicted smoker to experience withdrawal-induced craving for nicotine whenever the effect of nicotine wears off (Figure 4). In novice smokers, it may take several weeks for the down-stream effects of nicotine to wear off, and consequently the latency from the last cigarette to the onset of withdrawal-related craving may be several weeks.

Bottom Line: One such theory, the sensitization-homeostasis (SH) model, postulates that nicotine suppresses craving circuits, and this triggers the development of homeostatic adaptations that autonomously support craving.Over the past decade, many controversial aspects of the SH model have become well established by the literature, while some details have been disproven.We conclude by outlining directions for future research based on the updated model, and commenting on how new experimental studies can gain from the framework put forth in the SH model.

View Article: PubMed Central - PubMed

Affiliation: Department of Family Medicine and Community Health, University of Massachusetts Medical School, 55 Lake Avenue, Worcester, MA 01655, USA. difranzj@ummhc.org.

ABSTRACT
The role of neuronal plasticity in supporting the addictive state has generated much research and some conceptual theories. One such theory, the sensitization-homeostasis (SH) model, postulates that nicotine suppresses craving circuits, and this triggers the development of homeostatic adaptations that autonomously support craving. Based on clinical studies, the SH model predicts the existence of three distinct forms of neuroplasticity that are responsible for withdrawal, tolerance and the resolution of withdrawal. Over the past decade, many controversial aspects of the SH model have become well established by the literature, while some details have been disproven. Here we update the model based on new studies showing that nicotine dependence develops through a set sequence of symptoms in all smokers, and that the latency to withdrawal, the time it takes for withdrawal symptoms to appear during abstinence, is initially very long but shortens by several orders of magnitude over time. We conclude by outlining directions for future research based on the updated model, and commenting on how new experimental studies can gain from the framework put forth in the SH model.

No MeSH data available.


Related in: MedlinePlus