Recent findings by University of Sydney scholars are indicating that medications that boost the effect of natural brain opioids might help to reduce anxiety better than ‘receptor-binding’ opioid drugs such as morphine, which can have major side effects.
The human body is a complex machine. Medical News Today writes that fear and anxiety (which help to protect us from harm), “are largely controlled via neural circuits of interconnected nerve cells and synaptic activity in the brain’s amygdala which allow neurons to pass electrical or chemical signals to each other.” Specialized neural circuits control these emotions, however, any disturbances in these circuits can trigger prolonged and disabling emotional responses that are out of proportion to threatening events.
It is these kinds of disturbances which are thought to underpin many anxiety disorders such as phobias and even post-traumatic stress disorder, which affects up to one million Australians each year. In fact, anxiety disorders affect 14 percent of Australians, but they are poorly managed by commonly prescribed medications including benzodiazepines and 5HT-reuptake inhibitors. Elena Bagley, the University of Sydney’s Associate Professor who led the study, says that ,”These drugs weren’t developed to treat anxiety but they’re widely used because of chance findings suggesting their clinical usefulness.”
She, as well as many other experts, hopes that better anxiety treatments will be developed once science discovers how the neural circuits and endogenous or naturally occurring opioids regulate fear and anxiety. She feels that better insights are needed because the exact action of these natural opioids in the brain is not yet fully understood. These opioids control how we acquire and store memories of fear and what also helps to regulate our emotional responses once a threat has passed.
By ‘deleting’ the natural opioid enkephalin when doing experiments on mice (which is heavily expressed in the brain’s amygdala), their fear, anxiety and aggressiveness was increased. In contrast, if enkephalin was increased or breakdown reduced, these behaviors decreased.
Although this effect of enkephalin suggests that it is anxiety-inhibiting, the study showed that when it binds to the delta-opioid receptor, it inhibits it. Dr. Bagley says, “Given this complexity, understanding the cellular actions of natural opioids at these two receptors is critical if we hope to use opioid-related medications for emotional issues.”
She concludes the findings by saying that “opioids produced and released by our own brain cells strongly regulate these critical neural circuits that are important for fear responses. We also show that we could boost the actions of these endogenous opioids using a novel pharmacological approach.”