Biomaterial Database

Marking the tip location of PO2 microelectrodes or glass micropipettes. 1980

P Nair, and J I Spande, and W J Whalen

The necessity of localizing the PO2 recording sites in the carotid body of cats has led us to modify our O2 microelectrode to be able to mark the position of the tip. Gold is sputtered on the electrode, and then iron is plated on the gold. The carotid body of cats was exposed, and PO2 was recorded at different depths in the body after which iron was deposited. At the end of the experiment, the excised body was placed in a 1:1 mixture of 4% potassium ferrocyanide and 4% acetic acid for 1 h or more. After that, the body was fixed in a 1:1 mixture of 40% formaldehyde and 95% ethyl alcohol for 1-2 days. Paraffin sections cut at 10 micrometer revealed the recording sites as bright blue spots. Since the cathode size can be made as small as 1 micrometer, discrete spots (a few microns or larger depending on current and time) can be produced at the PO2 recording sites. Several locations can be marked in a few minutes without damage to the tissue or the electrode. In 21 cats all of the 62 marked spots were found. In 16 peripheral (depth 50-150 micrometers) locations the PO2 averaged 101 Torr and in 46 deep locations 73 Torr. This technique is applicable to glass micropipettes and is a unique tool in correlating the structure and function of various tissues.

UI	MeSH Term	Description	Entries
D008839	Microelectrodes	Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)	Electrodes, Miniaturized,Electrode, Miniaturized,Microelectrode,Miniaturized Electrode,Miniaturized Electrodes
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D010101	Oxygen Consumption	The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)	Consumption, Oxygen,Consumptions, Oxygen,Oxygen Consumptions
D002344	Carotid Body	A small cluster of chemoreceptive and supporting cells located near the bifurcation of the internal carotid artery. The carotid body, which is richly supplied with fenestrated capillaries, senses the pH, carbon dioxide, and oxygen concentrations in the blood and plays a crucial role in their homeostatic control.	Glomus Caroticum,Bodies, Carotid,Body, Carotid,Caroticum, Glomus,Carotid Bodies
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D005898	Glass	Hard, amorphous, brittle, inorganic, usually transparent, polymerous silicate of basic oxides, usually potassium or sodium. It is used in the form of hard sheets, vessels, tubing, fibers, ceramics, beads, etc.
D006046	Gold	A yellow metallic element with the atomic symbol Au, atomic number 79, and atomic weight 197. It is used in jewelry, goldplating of other metals, as currency, and in dental restoration. Many of its clinical applications, such as ANTIRHEUMATIC AGENTS, are in the form of its salts.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia