Isolation and Cannulation of Cerebral Parenchymal Arterioles

Abstract

Intracerebral parenchymal arterioles (PAs), which include parenchymal arterioles, penetrating arterioles and pre-capillary arterioles, are high resistance blood vessels branching out from pial arteries and arterioles and diving into the brain parenchyma. Individual PA perfuse a discrete cylindrical territory of the parenchyma and the neurons contained within. These arterioles are a central player in the regulation of cerebral blood flow both globally (cerebrovascular autoregulation) and locally (functional hyperemia). PAs are part of the neurovascular unit, a structure that matches regional blood flow to metabolic activity within the brain and also includes neurons, interneurons, and astrocytes. Perfusion through PAs is directly linked to the activity of neurons in that particular territory and increases in neuronal metabolism lead to an augmentation in local perfusion caused by dilation of the feed PA. Regulation of PAs differs from that of better-characterized pial arteries. Pressure-induced vasoconstriction is greater in PAs and vasodilatory mechanisms vary. In addition, PAs do not receive extrinsic innervation from perivascular nerves — innervation is intrinsic and indirect in nature through contact with astrocytic endfeet. Thus, data regarding contractile regulation accumulated by studies using pial arteries does not directly translate to understanding PA function. Further, it remains undetermined how pathological states, such as hypertension and diabetes, affect PA structure and reactivity. This knowledge gap is in part a consequence of the technical difficulties pertaining to PA isolation and cannulation. In this manuscript we present a protocol for isolation and cannulation of rodent PAs. Further, we show examples of experiments that can be performed with these arterioles, including agonist-induced constriction and myogenic reactivity. Although the focus of this manuscript is on PA cannulation and pressure myography, isolated PAs can also be used for biochemical, biophysical, molecular, and imaging studies.

Influence of dual‐specificity protein phosphatase 5 on mechanical properties of rat cerebral and renal arterioles

“…It has been traditionally thought that small pial, penetrating, and parenchymal arterioles account for the remainder of autoregulation of CBF and the fine regulation of capillary pressure (Federico et al, ; Iadecola & Davisson, ). In this study, the intracerebral PAs we used are the lenticulostriate branches of the MCAs, which provide blood supply to the frontoparietal white matter tracts and the basal ganglia in rats (Johnson & Cipolla, ; Pires et al, ). Embolism of these vessels is the most common cause of ischemic stroke in humans (Navarro‐Orozco & Sanchez‐Manso, ).…”

“…A piece of the brain surrounding the MCA was removed and transferred to another dish filled with ice‐cold PSS 0Ca supplemented with 1% bovine serum albumin (BSA) for vascular dissection. PAs branching directly from the M1 segment of MCA were carefully dissected (Cipolla, Chan, et al, ; Cipolla, Sweet, et al, ; Pires, Dabertrand, & Earley, ) under a microscope and mounted on glass micropipettes in a chamber filled with warmed (37°C), oxygenated (21% O 2 , 5% CO 2 , and 74% N 2 ) PSS.…”

Neuroprotective effects of TRPA1 channels in the cerebral endothelium following ischemic stroke

“…The effects of TRPA1 agonists and hypoxia were also assessed in freshly isolated cerebral penetrating arterioles. Isolation of penetrating arterioles was performed as previously described ( Pires et al, 2016 ). Briefly, penetrating arterioles branching out of the middle cerebral artery were carefully isolated from the surrounding parenchyma and mounted onto glass cannulas in a blind-sac experimental configuration.…”

Nanoscale remodeling of ryanodine receptor cluster size underlies cerebral microvascular dysfunction in Duchenne muscular dystrophy

“…Passive diameter at each pressure was determined by superfusing with Ca 2+ -free PSS (119 mM NaCl, 4.7 mM KCl, 1.8 mM CaCl 2 , 1.2 mM MgSO 4 , 21 mM NaHCO 3 , 1.18 mM KH 2 PO 4 , 4 mM glucose, 0.03 mM EDTA, and 2 mM EGTA) containing 0.01 mM diltiazem. Parenchymal arterioles were isolated and studied according to a protocol recently described by our laboratory ( 50 ).…”