Effects on respiration and circulation of electrically stimulating the ventral surface of the medulla oblongata

The pH of brain extracellular fluid in the cat

“…over the medulla and calibrated them in vivo by perfusing buffered, mock c.s.f. the composition of which was that described by SchlAfke, See & 146 BRAIN EXTRACELLULAR pH Loeschcke (1970) at pH of 6*8, 7'34 and 8*0. We then equilibrated this mock c.s.f.…”

“…First, we have measured only short-term responses lasting at most for a few minutes since we believe that these are more relevant to everyday changes in acid-base balance than the long-term changes which accompany acclimatization to altitude or chronic, non-respiratory acidosis or alkalosis which have been studied previously (Mitchell, Carman, Severinghaus, Richardson, Singer & Schneider, 1965). Secondly, we have been particularly concerned with the changes in pH which occur in or over the ventro-lateral surface of the medulla since it is here that H+ sensors have been proposed (Mitchell, Loeschcke, Massion & Severinghaus, 1963; Schlifkie, See & Loeschcke, 1970). We have used as control, areas in the parietal cortex where neurones, sensitive to changes in Pco, have been observed (Krnjevi6 138 BRAIN EXTRACELLULAR pH Randic & Siesj6, 1965) but which have not (yet) been shown to affect respiratory neurones directly.…”

Mechanisms of CO2/H+ chemoreception by respiratory rhythm generator neurons in the medulla from newborn rats in vitro

“…Chemosensitive regions have been found in the ventral medullary surface (Mitchell et al 1963;Schlaefke et al 1970;Loeschcke et al 1970). Because no intrinsically chemosensitive neuron has been identified there, Loeschcke (1982) suggested that the synaptic mechanism located in the chemosensitive areas of the ventral surface of the medulla is responsible for the chemosensitivity of respiration.…”

Inspiratory response to occlusion of arteries in the ventral surface of the medulla in anesthetized cats.

“…The first possibility has been proposed by Mitchell et al (1963) and Loeschcke et al (1970). They demonstrated that there were two separate chemosensitive areas in the ventral surface of the medulla, the 'Rostral (M)' and `Caudal (L)' areas.…”

“…Three separate areas concerning the central chemosensitive mechanism, the 'Rostral (M)', `Intermediate (S)' and `Caudal (L)' areas , have been described (Mitchell et al 1963; Schldfke et al 1969; Loeschcke et al 1970;Loeschcke 1982). However, there is still uncertainty about both the actual location and the effective stimulus of the chemosensitive elements, as shown in recent reviews (Millhorn and Eldridge 1986;Bruce and Cherniack 1987).…”