TY - JOUR
T1 - Time-dependent phrenic nerve responses to carotid afferent activation
T2 - Intact vs. decerebellate rats
AU - Hayashi, F.
AU - Coles, S. K.
AU - Bach, K. B.
AU - Mitchell, G. S.
AU - McCrimmon, Donald R
PY - 1993/1/1
Y1 - 1993/1/1
N2 -
The objectives were to determine 1) respiratory responses to carotid chemoreceptor inputs in anesthetized rats and 2) whether the cerebellar vermis plays a role in these responses. A carotid sinus nerve was stimulated (20 Hz) with five 2-min trains, each separated by ~3 min. During stimulation, respiratory frequency (f), peak amplitude of integrated phrenic nerve activity (∫Phr), and their product (f x ∫Phr) immediately increased. As stimulation continued, ∫Phr progressively increased to a plateau [short- term potentiation (STP)], but f and f x ∫Phr decreased [short-term depression (STD)] to a value still above control. Upon stimulus termination, ∫Phr progressively decreased but remained above control; f and f x ∫Phr transiently decreased below baseline. After the final stimulation, ∫Phr remained above control for at least 30 min [long-term facilitation (LTF)]. Repeated 5-min episodes of isocapnic hypoxia also elicited STP, STD, and LTF. Vermalectomy lowered the CO
2
-apneic threshold and eliminated LTF. In conclusion, carotid chemoreceptor activation in rats elicits STP and LTF similar to that in cats; the vermis may play a role in LTF. A new response, STD, was observed.
AB -
The objectives were to determine 1) respiratory responses to carotid chemoreceptor inputs in anesthetized rats and 2) whether the cerebellar vermis plays a role in these responses. A carotid sinus nerve was stimulated (20 Hz) with five 2-min trains, each separated by ~3 min. During stimulation, respiratory frequency (f), peak amplitude of integrated phrenic nerve activity (∫Phr), and their product (f x ∫Phr) immediately increased. As stimulation continued, ∫Phr progressively increased to a plateau [short- term potentiation (STP)], but f and f x ∫Phr decreased [short-term depression (STD)] to a value still above control. Upon stimulus termination, ∫Phr progressively decreased but remained above control; f and f x ∫Phr transiently decreased below baseline. After the final stimulation, ∫Phr remained above control for at least 30 min [long-term facilitation (LTF)]. Repeated 5-min episodes of isocapnic hypoxia also elicited STP, STD, and LTF. Vermalectomy lowered the CO
2
-apneic threshold and eliminated LTF. In conclusion, carotid chemoreceptor activation in rats elicits STP and LTF similar to that in cats; the vermis may play a role in LTF. A new response, STD, was observed.
KW - carotid sinus nerve
KW - cerebellum
KW - hypoxia
KW - long-term facilitation
KW - phrenic nerve
KW - rat
KW - respiratory control
KW - short-term potentiation
UR - http://www.scopus.com/inward/record.url?scp=0027443638&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027443638&partnerID=8YFLogxK
U2 - 10.1152/ajpregu.1993.265.4.r811
DO - 10.1152/ajpregu.1993.265.4.r811
M3 - Article
C2 - 8238451
AN - SCOPUS:0027443638
SN - 0002-9513
VL - 265
SP - R811-R819
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
IS - 4 34-4
ER -