|Budget Amount *help
¥6,400,000 (Direct Cost: ¥6,400,000)
Fiscal Year 1988: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1987: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1986: ¥2,800,000 (Direct Cost: ¥2,800,000)
I) Coexistence of neuroactive substances in single motor neurons We have previously shown the findings that acetylcholine (Ach) and calcitinin gene-related peptide coexist in single motor neurons. We determined, using pharmacological means, with a phrenic nerve diaphragm preparation, that this peptide enhances muscle contraction during stimulation of the nerve fibers or direct stimulation of the muscle. This effect is probably brought about via the receptor for this peptide not the Ach receptors. Furthermore, we have shown that CGRP also caused an increase in cyclic AMP in the striated muscle with a dose dependent manner.
II) Coexistence of neuroactive substances in single sensory neurons We have demonstrated that CGRP also coexists with substance P (SP) in single small sized neurons in the sensory ganglia. Nociceptive stimulation resuled in a enhancement of preprotachychinine A (PTTA) mRNA which codes SP in sensory neurons, indicating that SP related much more closely to the nociceptio
n conduction system. On the other hand, in the dorsal horn, SP coexists with enkephalin (Enk) in single neurons. Expression of preproenkephalin (PPE) mRNA increased within 1 hour after nociceptive stimulation, demonstrating that at the level of the dorsal horn of the spinal cord, Enk is related more closely to the nociception conducting system than SP.
III) Presence of neurons containing more than three neuroactive substances Lateral parabrachial area contains a number of CGRP-, SP-and neurotensin (NT)-containing neurons. Destruction of the external subnucleus of the lateral perabrachial area resuled in a disappearance of CGRP, SP and NT fiders in the central amygdaloid nucleus (AC). In addition, distribution pattern of these peptidergic neurons in the external subnucleus is very similar, suggesting that three kinds of peptides localize in single neurons here. In facts, immunocytochemical double staining analysis revealed that most of sp neurons here contained NT. Immunohistochemical analysis of alternative consecutive sections showed that many of these neurons also contained CGRP. In order to examine the significance of the coexistence of more than three neuroactive substances in single neurons, the localization neuroreceptors should be elucidated. We are now working on this problem. Less