Blood pressure pulsations modulate olfactory bulb neuronal activity via mechanosensitive ion channels

Abstract

The 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.

Viscoelastic high-molecular-weight hyaluronic acid hydrogels support rapid glioblastoma cell invasion with leader-follower dynamics

“…For mesenchymal stem cell (MSC) fate commitment, increasing viscous properties in a stiff matrix promotes greater MSC osteogenic differentiation whereas reducing viscous properties in a soft matrix promotes adipogenic differentiation. 5 Careful consideration of ECM viscous properties is particularly important in brain tissue, which is ~80% water 9 and exquisitely sensitive to external shear forces, 10 internal dynamics of blood and cerebrospinal fluid flow, 11 and changes in intracranial pressure. 12 For example, the viscoelasticity of brain tissue is increasingly understood to play important roles in the propagation of stresses in traumatic brain injury (TBI), 13 which has in turn spurred efforts to incorporate viscoelastic properties into therapeutic materials for healing brain lesions associated with TBI and other pathologies.…”