Cardiovascular and respiratory responses evoked from the posterior cerebellar cortex and fastigial nucleus in the cat.

Abstract

SUMMARY1. In both anaesthetized and decerebrate cats the cerebellar cortex (lobules VI, VII, VIII, IX and X) and the fastigial nucleus (f.n.) have been stimulated electrically, and chemically, while recording changes in phrenic nerve discharge, heart rate, arterial blood pressure and renal and femoral blood flow.2. Stimulation of lobules VI, VII, VIII and Xb failed to elicit any cardiovascular or respiratory changes. Activation of lobule IX (the uvula), and in some preparations sub-lobule Xa, evoked cardiovascular and respiratory responses consistently. In the anaesthetized cat, electrical stimulation of the uvula evoked apnoea, a small bradycardia and a depressor response associated with vasodilatation in the hindlimb vascular bed. In contrast, stimulation in an equivalent region in a decerebrate preparation elicited an apneustic discharge, a pronounced tachycardia and a rise in arterial pressure with vasoconstriction in both renal and femoral vascular beds. In both the anaesthetized and decerebrate animals the pattern of response elicited by chemical activation was identical to that seen with electrical stimulation.3. Electrical, or chemical, stimulation after administration of anaesthetic to the decerebrate cat then evoked an identical pattern of response to that seen in the 'intact' anaesthetized animal. This evidence suggests that the reversal in the pattern of the response is an effect of the anaesthetic agent and not the decerebration itself.4. The only area of the f.n. to produce cardiovascular effects was the rostral region.

Effects of bilateral vestibular nucleus lesions on cardiovascular regulation in conscious cats

“…During recording sessions, a cable was attached to the head-mounted connector to allow ECG signals to be fed to an amplifier (model 1700, A-M Systems, Carlsberg, WA); activity was amplified by a factor of 10 4 and filtered with a band pass of 10 -10,000 Hz. Subsequently, these signals were recorded digitally using a 1401-plus data collection system (Cambridge Electronic Design, Cambridge, UK) interfaced with Macintosh (Apple Computer, Cupertino, CA) G4 computer.…”

Neurogenic neuroprotection: Future perspectives

“…This response, discovered in 1969 by Miura and Reis [28] and Achari and Downman [26] in anesthetized cats, is known as "the fastigial pressor response" (FPR). In contrast, microinjection of excitatory amino acids, which only excite neuronal perikarya, decreases arterial pressure and heart rate [33,36,37]. These observations can explain the apparent paradoxical findings seen after indiscriminate FN electrical stimulation.…”

Proceedings of the Physiological Society, 30‐31 March 1990,University College London Meeting: Communications

“…Sinus inflation failed to affect these cells. (Bradley et al 1987). In the present experiments we have investigated the role of the posterior vermis in mediating classically conditioned bradyeardia to threatening stimuli.…”

“…In a second series of experiments, stimulating electrodes were positioned in the descending efferent pathway from the dorsal PAG, in the region of the synaptic relay in the rostral ventrolateral medulla (RVLM) (Lovick et al 1984 (Bradley et al 1987;Paton et al 1989 Thirty-two cells were studied from sites within the RVLM, which received inputs from IXb and will be divided into three groups on the basis of the action of spinal cord stimulation. In the first group, 20 cells responded with an all or none spike at constant latency to spinal cord stimulation.…”