Cardiovascular roles of tachykinin peptides in the nucleus tractus solitarii of rats.
Unilateral removal of the afferent fibers of the IXth and Xth cranial nerve (nodose ganglionectomy) caused significant decrease in the content of substance P-like immunoreactivity (SP-LI) and neurokinin A-like immunoreactivity (NKA-LI) in the nucleus tractus solitarii (NTS) of rats. Microinjection of SP (1 ng) or NKA (10-100 ng) into the NTS caused prompt, transient hypotension and bradycardia, suggesting that SP and NKA may be neurotransmitters of the baroreceptor reflex in the NTS. NKB-like immunoreactivity (NKB-LI) was also detected in the NTS of rats by radioimmunoassay, but its content in the NTS was not affected by unilateral nodose ganglionectomy. The microinjection of 1-10 ng of suc-[Asp5, Me-Phe8]-SP(6-11) (senktide, a selective neurokinin B receptor peptide) into the NTS caused long-lasting hypertension and tachycardia. These results indicate that NKB may also be a neuromodulator on cardiovascular responses in the NTS.
Nagashima
A
A
Department of Pharmacology, Faculty of Pharmaceutical Science, Fukuoka University, Japan.
Takano
Y
Y
Tateishi
K
K
Matsuoka
Y
Y
Hamaoka
T
T
Kamiya
H
H
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008845:Microinjections; D015288:Neurokinin A / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D015287:Neurokinin B / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*
D010446:Peptide Fragments; C054724:senktide; D013373:Substance P; D015288:Neurokinin A; D015287:Neurokinin B