革胡子鲇触须味蕾及其味觉反应的研究

GUSTATION AND TASTE ORGAN IN THE BARBEL OF THE AFRICAN CATFISH

  • 摘要: 革胡子鲇(Clarias gariepinus)上颌须有体表味蕾存在,约为12个/mm2,由通过眼眶后下缘的面神经分枝联系.用电生理学方法记录传入神经冲动,测定上颌须味蕾对多种动物组织浸提液和氨基酸的味觉敏感性.除甘氨酸、L-脯氨酸、L-色氨酸和L-酪氨酸外,多数刺激物能引起有效的昧觉反应.氨基酸中,L-精氨酸刺激最有效,阈值低达10-7mol/L左右.氨基酸引起的味觉反应与浸提液的反应特性相似;快适应;位相性反应;高浓度刺激下出现饱和.各种刺激物的味觉反应的阈值、反应速率和相对反应强度有不同,由电生理记录得到的敏感性结果可在行为学实验中得到验证,并发现体表昧蕾的味觉反应与鱼类的摄饵行为有关.饵料中的游离氨基酸可能是这种行为的引诱剂.

     

    Abstract: The maxillary barbel of the African catish,Clarias gariepinus, contains epidermalchemosensory organs, the taste buds.It was estimated that there are 12 taste buds in eachmm2 of the maxillary barbel epidennis.The gustatory sensitivity to the extracts of animal tissues and amino acids was studied by recording the neural responses from thebranch of the facial nerve innervating the maxillary barbel.Positive gustatory responses to the tested stimulatory compounds,except Glycine,L-proline,L-Tryptophan and L-Tyrosine, were observed.Among the amino acids tested, the most potent stimulus is L-Arginine which has an approximate electro-physiological threshold of 10-7 mol / L. The taste responses to amino acids and the extracts have similar characteristics,rapid adaptation,phasic response,and saturation athigh concentrations.However,the threshold,the gradient and the response magnitudefor the chemicals tested at same concentrations in the present study are different fromone stimulus to another. The more sensitive stimuli by electrophysiological recordings are also the more effective feeding-stimulatory substance. The results indicate further that the gustatory responses of the epidermal taste buds are related with the exploratory and feeding behaviorin african catfish.It is suggested that some water-Soluble amino acids in feeds may evokefeeding responses.

     

/

返回文章
返回