Intraluminal pressure elevates intracellular calcium and contracts CNS pericytes: Role of voltage-dependent calcium channels. 2023

Nicholas R Klug, and Maria Sancho, and Albert L Gonzales, and Thomas J Heppner, and Rochelle Irene C O'Brien, and David Hill-Eubanks, and Mark T Nelson
Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT 05405.

Arteriolar smooth muscle cells (SMCs) and capillary pericytes dynamically regulate blood flow in the central nervous system in the face of fluctuating perfusion pressures. Pressure-induced depolarization and Ca2+ elevation provide a mechanism for regulation of SMC contraction, but whether pericytes participate in pressure-induced changes in blood flow remains unknown. Here, utilizing a pressurized whole-retina preparation, we found that increases in intraluminal pressure in the physiological range induce contraction of both dynamically contractile pericytes in the arteriole-proximate transition zone and distal pericytes of the capillary bed. We found that the contractile response to pressure elevation was slower in distal pericytes than in transition zone pericytes and arteriolar SMCs. Pressure-evoked elevation of cytosolic Ca2+ and contractile responses in SMCs were dependent on voltage-dependent Ca2+ channel (VDCC) activity. In contrast, Ca2+ elevation and contractile responses were partially dependent on VDCC activity in transition zone pericytes and independent of VDCC activity in distal pericytes. In both transition zone and distal pericytes, membrane potential at low inlet pressure (20 mmHg) was approximately -40 mV and was depolarized to approximately -30 mV by an increase in pressure to 80 mmHg. The magnitude of whole-cell VDCC currents in freshly isolated pericytes was approximately half that measured in isolated SMCs. Collectively, these results indicate a loss of VDCC involvement in pressure-induced constriction along the arteriole-capillary continuum. They further suggest that alternative mechanisms and kinetics of Ca2+ elevation, contractility, and blood flow regulation exist in central nervous system capillary networks, distinguishing them from neighboring arterioles.

UI MeSH Term Description Entries
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002136 Calcium, Dietary Calcium compounds in DIETARY SUPPLEMENTS or in food that supply the body with calcium. Dietary Calcium
D002490 Central Nervous System The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges. Cerebrospinal Axis,Axi, Cerebrospinal,Axis, Cerebrospinal,Central Nervous Systems,Cerebrospinal Axi,Nervous System, Central,Nervous Systems, Central,Systems, Central Nervous
D001160 Arterioles The smallest divisions of the arteries located between the muscular arteries and the capillaries. Arteriole
D020286 Pericytes Unique slender cells with multiple processes extending along the capillary vessel axis and encircling the vascular wall, also called mural cells. Pericytes are imbedded in the BASEMENT MEMBRANE shared with the ENDOTHELIAL CELLS of the vessel. Pericytes are important in maintaining vessel integrity, angiogenesis, and vascular remodeling. Rouget Cells,Cells, Rouget,Pericyte
D020746 Calcium Channels, L-Type Long-lasting voltage-gated CALCIUM CHANNELS found in both excitable and non-excitable tissue. They are responsible for normal myocardial and vascular smooth muscle contractility. Five subunits (alpha-1, alpha-2, beta, gamma, and delta) make up the L-type channel. The alpha-1 subunit is the binding site for calcium-based antagonists. Dihydropyridine-based calcium antagonists are used as markers for these binding sites. Dihydropyridine Receptors,L-Type Calcium Channels,L-Type VDCC alpha-1 Subunit,L-Type Voltage-Dependent Calcium Channel,Long-Lasting Calcium Channel,Long-Lasting Calcium Channels,Receptors, Dihydropyridine,Dihydropyridine Receptor,L-Type Calcium Channel,L-Type VDCC,L-Type VDCC alpha-2 Subunit,L-Type VDCC beta Subunit,L-Type VDCC delta Subunit,L-Type VDCC gamma Subunit,L-Type Voltage-Dependent Calcium Channels,Calcium Channel, L-Type,Calcium Channel, Long-Lasting,Calcium Channels, L Type,Calcium Channels, Long-Lasting,Channel, Long-Lasting Calcium,L Type Calcium Channel,L Type Calcium Channels,L Type VDCC,L Type VDCC alpha 1 Subunit,L Type VDCC alpha 2 Subunit,L Type VDCC beta Subunit,L Type VDCC delta Subunit,L Type VDCC gamma Subunit,L Type Voltage Dependent Calcium Channel,L Type Voltage Dependent Calcium Channels,Long Lasting Calcium Channel,Long Lasting Calcium Channels,Receptor, Dihydropyridine,VDCC, L-Type

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