Issue Archive

Effects of carotid baro-and chemoreceptor stimulation on the single unit activity of nucleus paragigantocellularis lateralis

Luo Hong, Ho Shiuyong

Department of Physiology, Institute of Basic Medicine, Hebei Medical College. Hebei, China

Abstract

The effects of selective activation of carotid baro- and chemoreceptor on the
single unit activity of the nucleus paragigantocellularis lateralis (PGL) in ventrolateral medulla were studied in 31 cats under #alpha#-chloralose and urethan anesthesia. Of the 136 units with spontaneous discharge in the PGL, 84 showed some change of discharge frequency in response to the activation of carotid baroreceptor (phenylephrine, 1-2/#mu#g/kg iv) (BA) and/or chemoreceptor nicotine, 5-20#mu#g, injected into the thyroid artery) (CA). Of these 84 units, 16 responded only to CA (11 excited and 5 inhibited), 54 responded with various patterns to both CA and BA,in which majority of the units were excited by CA and inhibited by BA, and 14 responded only to BA (7 excited, 7 nhibited). Topographically, the units responsive only to CA were primarily located in the ventral part of the PG L, the units responsive only to BA located dorsally, and the units responsive both to BA and CA located in the middle or more dorsal part of the PGL. These results showed that the informations from carotid baro-and chemoreceptor were conveyed to P GL and converged on some neurones. In all responsive units of the PGL, 68 responded to baroreceptor activation, in which 29 were excited and 39 were inhibited (P j0.05), and 70 responded to chemoreceptor activation, in which 48 were excited and 22 were inhibited (P<0.005).These results suggested that the neurones in PGL were either activated or inactivated by BA, but mainly activated by CA.

Key words: Carotid chemoreceptor;Carotid baroreceptor;Nucleus paragigantocellularia lateralis;Single unit discharge;Ventrolateral medulla

Received: 　　Accepted:

Corresponding author: 　　E-mail:

Citing This Article：

Luo Hong, Ho Shiuyong. Effects of carotid baro-and chemoreceptor stimulation on the single unit activity of nucleus paragigantocellularis lateralis. Acta Physiol Sin 1987; 39 (5): (in Chinese with English abstract).