2001 Fiscal Year Final Research Report Summary
Platelets as a marker of adrenergic and serotonergic receptors in dogs
| Project/Area Number |
11660313
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied veterinary science
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| Research Institution | Tottori University |
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Principal Investigator |
HIKASA Yoshiaki Tottori University, Faculty of Agriculture, Professor, 農学部, 教授 (30165071)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Kota Tottori University, Faculty of Agriculture, Assistant Professor, 農学部, 講師 (50283974)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Dog / Platelet / Adrenoceptor / Imidazoline receptor / Guanine nucleotide / Adrenaline / Serotonin / GTP binding protein |
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| Research Abstract |
The present study was conducted to investigate the platelet activity as a marker of adrenergic, non-adrenergic, and serotonergic receptors in dogs, based on previous findings that monoamine, and in particular 5-hydroxytryptamine in the brain, are involved in the regulation of α_2-adrenoceptor-mediated emesis. This study demonstrated that the α_<2A>-adrenoceptor subtype exists on canine platelets, and this type of receptors was involved in the mediation of adrenaline-potentiated platelet aggregation. The results of α_2-adrenoceptor binding and the α_2-adrenoceptor-mediated cardiovascular effects during canine endotoxin shock revealed that significant positive correlations were observed for reduced number of α_2-adrenoceptors between platelets and brain, and diminished cardiovascular effects of α_2-adrenoceptor agonists. Therefore, the α_<2A>-adrenoceptor activity was impaired in the central nervous system as well as in the peripheral vascular system during canine endotoxin shock. These results indicated that platelets may in part represent a good model which reflects the α_2-adrenoceptor changes in the central nervous system and peripheral vascular system during and after activation of sympatho-adrenal nerve activity. On the other hand, this study demonstrated that imidazol(in)e (I) structure has a role for inhibition of adrenaline-potentiated platelet aggregation in dogs, and that two subtypes of non-adrenergic I receptors, I_1 and I_2, exist on canine platelets. In addition, this study suggested that I_1 subtype was coupled with GTP-binding proteins, and I_2 was not coupled with those. Further studies may be required to investigate the function of I_1 and I_2 receptors as well as 5-HT receptors in canine platelets.
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