Effect of carotid body denervation on breathing in neonatal goats.

The objective of the present study was to determine in goats whether carotid body denervation (CBD) at 1-3 days of age causes permanent changes in breathing greater than those that occur after CBD in adult goats. Goats underwent CBD (n = 6) or sham CBD (n = 3) surgery at 1-3 days of age. In addition, one unoperated control animal was studied.

Effects of cooling the ventrolateral medulla on diaphragm activity during NREM sleep.

Dysfunction through cooling of neurons near the ventrolateral medullary (VLM) surface results in apnea in the anesthetized state, whereas similar neuronal dysfunction in the awake state only modestly decreases breathing. The purpose of this study was to investigate effects on breathing, as measured by diaphragm electromyogram (EMGdi), of VLM neuronal dysfunction during NREM sleep, a naturally occurring change in state. In six goats, thermodes for cooling were chronically implanted between the first hypoglossal rootlet and the pontomedullary junction (area M and area S).

Effect on breathing of ventral medullary surface cooling in neonatal goats.

The present study was designed to determine whether neurons near the ventral medullary surface (VMS) that are important to control of breathing in adult mammals are also important to control of breathing in neonates. In 7-day-old goats (n = 22), the VMS was surgically exposed under halothane anesthesia. Stainless steel thermodes (2 x 2 mm) were used to cool (20 degrees C) and thereby create neuronal dysfunction of discrete VMS sites.

Effect of dichloroacetate on PaCO2 responses to hypoxia in awake goats.

To gain insight into the role of cerebral lactic acidosis in the hypoxic ventilatory response, we administered dichloroacetate (DCA) intravenously to inhibit lactic acid production in 7 awake goats (40-70 kg) during 0.5 h of normoxia (inspired O2 fraction = 0.209) and 5 h of poikilocapnic hypoxia (inspired O2 fraction = 0.

Effect on breathing of neuronal dysfunction in the caudal ventral medulla of goats.

It has been reported that the caudal ventrolateral medulla (VLM) is important in central chemoreception and the control of breathing. The objective of this study was to determine in adult goats the effects on breathing of neuronal dysfunction of this caudal VLM region (area L; caudal to rostral hypoglossal nerve rootlet). Thermodes were chronically implanted on the VLM to cool neurons and thereby cause neuronal dysfunction.