In a study published by Frontiers in Behavioral Neuroscience, one of the main class of prescription sleeping pills was found to reduce the ability to wake up to dangerous alerting signals. In particular, the study found that half the participants could not wake-up from the sound of a fire alarm as loud as the sound of a vacuum next to their bed.
Even while sleeping the brain continuously processes sensory information and will wake us up if a threat was detected—such as a loud bang. The most widely prescribed sleeping pills are benzodiazepines, which will most likely not rouse in response to sensory input. "Benzodiazepines stimulate the widespread brain receptor GABA-A, which makes us sleepy but also suppresses off-target brain areas -- including the 'gatekeeper' that decides which sensory inputs to process," says study senior author, Professor Tomoyuki Kuwaki of Kagoshima University, Japan.
However, the last decade included the development of a new class of hypnotic drugs known as dual orexin receptor antagonists (DORAs). These drugs work by selectively targeting certain sleep/wake pathways in the brain—making them more advantageous in regards to safety over benzodiazepines, including a reduced 'hangover effect' that will less likely affect driving ability after use.
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The researchers then hypothesized that the selectivity of DORAs could be a safer alternative, than another tested benzodiazepine called triazolam since it was confirmed in model mice that DORA-22 allowed the mice to sleep but still wake to a threat. "DORA-22 and triazolam had similar sleep promoting effects, extending the duration of deep sleep by 30-40% compared to placebo," reported Kuwaki. "As expected, arousal in response to these threatening stimuli was delayed significantly in the triazolam treatment, but not in the DORA-22 treatment, compared to placebo.
However, to help confirm the safety and efficacy of the sleep-promoting effect of DORA in humans—clinical studies are needed after approval. "Although it remains to be seen whether DORAs have the same properties when used in humans, our study provides important and promising insight into the safety of these hypnotics."
Source: Science Daily