How sensing blood pressure alters stress

Stress and ageing are both unavoidable features of any life. Blood pressure increases steadily with age which, whilst normal, can impact quality of life and healthy ageing. Individuals with elevated blood pressure demonstrate enhanced responses to stress, but the mechanisms underlying this are only partially understood.
Blood pressure is continuously sensed by stretch-sensitive terminals called baroreceptors, which are located in the heart and neck. In response to high blood pressure, these baroreceptors signal to a part of the brain, in the lower brainstem, called the nucleus of the solitary tract (NTS). The NTS responds by adjusting heart rate and blood pressure, but the NTS is also well-known to control anxiety and stress responses. We think that elevated blood pressure leads to increased stress responses at least partly as a result of lower sensitivity to baroreceptor signals.
To investigate this, we will first test if brief changes to blood pressure impact anxiety-like behaviours in mice. Next, we will determine if this is controlled by baroreceptor signals by turning their activity on or off while measuring anxiety-like behaviours. We also aim to understand which cells in the NTS may be involved. Finally, we will investigate if baroreceptors and their communication with the brain are changed after long-term elevated blood pressure, and, if this is partly the reason for increased responses to stress.
Taken together, these studies will further our understanding of the role of blood pressure regulation and its impact on healthy ageing. In doing so, there may be the potential to promote healthy ageing and improve the quality of life for those with elevated blood pressure.