Blood pressure pulsations modulate olfactory bulb neuronal activity via mechanosensitive ion channels
AbstractThe transmission of heartbeat through the cerebral vascular system is known to cause intracranial pressure pulsations. Here we describe that arterial pressure pulsations within the brain can directly modulate central neuronal activity. In a semi-intact rat brain preparation, pressure pulsations elicit correlated local field oscillations in the olfactory bulb (OB) that are sensitive to hypoxia and block of mechanosensitive channels. We find that mitral cell spiking activity is in part synchronized to these oscillations. Indeed, in awake animals the firing of a subset of OB neurons is entrained to heartbeat within [~] 20 ms. Several lines of evidence indicate the expression of a mechanosensitive ion channel within the mitral cell membranes, most likely Piezo2, implementing a pressure pulsation transduction pathway and thus baroreception within the OB. We propose that this intrinsic interoceptive mechanism modulates OB neuronal activity e.g. during arousal and also could influence brain activity on a wider scale.