Neurotransmitters and the Chemical Effect of Dependency
Neurotransmitters, or NTs, are chemicals that allow signal transmission, or communication, between nerve cells and play an important role in the activation of specific feelings and emotions in addition to influencing how we react to our environment or circumstance. There are a wide variety of NTs important in the function of a healthy brain, but of primary importance for alcoholics and addicts a few very specific chemical messengers take center stage. In the disease of addiction, dopamine, serotonin and beta-endorphin often become depleted or their function inhibited, leaving an alcoholic or addict susceptible to a wide variety of unsavory biochemical adaptations that may hinder the recovery process and contribute to emotional instability and more severe dependence.
In the brain, dopamine plays an important role in reward-motivated behavior. Every fathomable variety of reward inducing substance increases dopamine levels in the brain, but addictive substances alter its production and amplify its effect. For example, hyper-palatable foods have the ability to ignite dopamine production, but their effect is controlled to the extent that their efficacy is marginalized with continued consumption. However, drugs bypass the adaptive mechanism that constrains the reward system to promote seeking behavior and the addiction process, which ultimately increases impulsivity while impairing impulse control and decision-making.
Unfortunately, this reward system is so powerful that it reinforces heavy consumption of alcohol and encourages dependence, which may cause genetic alterations that increase alcohol preference in future generations.
Serotonin, probably most well known for its ability to contribute to feelings of happiness and well-being, is largely depleted by short- and long-term alcohol exposure and can interfere with serotonin receptors, leading to adaptive changes that down-regulate serotonin production and facilitate tolerance development. The process of serotonin depletion and down-regulation greatly contributes to withdrawal symptoms that include anxiety and depression after cessation, which may encourage greater and more frequent alcohol consumption. This relationship has been studied extensively in both human and animal models and is of paramount importance in reward-motivated or alcohol-seeking behavior.
Unfortunately, the relationship between alcohol and serotonin doesn’t end with anxiety and depression. Alcohol induced serotonin depletion has been found to be associated with highly aggressive behavior in response to environmental or psychological provocation.
Endorphins are neurotransmitters that are produced during exercise, excitement, pain, love, and orgasm and resemble opiates in their ability to stimulate feelings of wellbeing. The effects of endorphins are often experienced as a ‘rush’, or what is commonly referred to as the ‘runner’s high’, which provides feelings of exhilaration in response to pain, danger or other forms of stress.
Beta-endorphins, one of the more important iterations of endorphin for our purposes, affects feelings of self-esteem, the capacity to handle painful situations, and feelings of hope or despair about the future, which is of particular importance in our discussion on the effects that neurotransmitters have upon alcoholic behavior and alcoholism. For example, the consumption of alcohol results in an increase in beta-endorphin levels in the brain, which are associated with reward and seeking behavior. It has also been observed that the habitual consumption of alcohol leads to beta-endorphin deficiency, which alters mood and wellbeing. Making matters worse, the beta-endorphin system in individuals with a family history of alcoholism shows an enhanced sensitivity to ethanol, which has been shown to have a tremendous influence upon alcohol preference.
NTs and Diet
As we discussed in last week’s post Eating to Prevent Alcohol Cravings and Relapse, wild surges in blood glucose caused by the consumption of alcohol or high glycemic foods interact with the brain’s dopamine system and influences reward-motivated behavior, which may lead to dependence. And, as simple as it may sound, serotonin production and the beta-endorphin system are dependent upon blood sugar in much the same way. Chronically elevated blood sugar levels (hyperglycemia) lead to excessive release and depletion of both serotonin and beta-endorphin to over stimulate the brain’s reward center and produce feelings of extreme euphoria. When blood sugar is consistently too low (hypoglycemia), the body will send out distress signals that it is running low on fuel, which will ignite cravings for simple sugars like alcohol and high GI foods in order to help restore balance. Both hyper- and hypoglycemia prime the mind and body for neurotransmitter dysfunction and dependence.
Our neurological and emotional wellbeing is dependent upon the efficient production of the neurotransmitters dopamine, serotonin, and beta-endorphin, which are highly dependent upon positive blood glucose and, therefore, diet.
Image courtesy of the amazing and very talented Maverick Shaw