Enzymatic inactivation of tachykinin neurotransmitters in the isolated spinal cord of the newborn rat.
A mixture of peptidase inhibitors increased the magnitude of the saphenous nerve-evoked slow depolarization of a lumbar ventral root and prolonged the similarly evoked inhibition of monosynaptic reflex (MSR) in the isolated spinal cord of the newborn rat in the presence of naloxone. The saphenous nerve-evoked MSR inhibition was curtailed by a tachykinin antagonist, GR71251, and after the treatment with GR71251, the peptidase inhibitor mixture no more prolonged the MSR inhibition. The present results suggest that enzymatic degradation plays a role in the termination of action of tachykinins released from primary afferents in the newborn rat spinal cord. The results provide a further support for the notion that tachykinins serve as neurotransmitters in the spinal cord of the newborn rat.
Yanagisawa
M
M
Department of Pharmacology, Faculty of Medicine, Tokyo Medical and Dental University, Japan.
Yoshioka
K
K
Kurihara
T
T
Saito
K
K
Seno
N
N
Suzuki
H
H
Hosoki
R
R
Otsuka
M
M
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism; D066298:In Vitro Techniques; D015288:Neurokinin A / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012023:Reflex, Monosynaptic / Q000187:drug effects; D013116:Spinal Cord / Q000201:enzymology*; D013373:Substance P / Q000494:pharmacology; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology; D015320:Tachykinins / Q000037:antagonists & inhibitors / Q000378:metabolism*
D018377:Neurotransmitter Agents; D011480:Protease Inhibitors; D015320:Tachykinins; D013373:Substance P; D015288:Neurokinin A; D010450:Endopeptidases