The cingulate cortex, especially its anterior portion has been found to be connected with the head of the caudate nucleus in our previous study. In order to ensure accurate placement of adequate amounts of HRP in the cingulate cortex, a microiontophoretic delivery technique coupled with single cell recording was employed. The use of electrophysiological criteria as aids in placing the injection is described in detail. It was found that the influence of the caudate neuron was inhibitory, and the cingulate neurons responded with monosynaptic IPSPs to caudate neuron stimulation. Following HRP injections into the cingulate cortex, the retrogradely labeled cells were found in the head of the caudate nucleus. It is obvious that some neurons of the head of caudate nucleus which have inhibitory effect on unit discharge of the cingulate cortex project to the anterior portion of the cingular cortex.

AIM: To study the recombinant plasmid pDL121 and its expression product in E.coli. METHODS: pDL121 was analysed by using 6 different restriction endonucleases and dot blotting, and the isolated 23 kDa protein band was cut and injected twice into rabbits to raise anti-23 kDa serum. RESULTS: The restriction map of pDL121 was quite different from other leptospiral genes reported and digoxin labeled recombinant DNA probe of pDL121 could detect the pathogenic leptospires, whereas, not the nonpathogenic leptospires. The anti-23 kDa serum could recognize the sonicated antigen of L.interrogans serovar lai strain 017 and 23 kDa protein expressed in pDL121 and the titer of the antiserum were very high, approximately 1/12 800. Injection of the E.coli lysate of pDL121 with Freund's adjuvant into guinea pigs resulted in some protection of the animal against the challenge with strain 017. CONCLUSION: It indicated that 23 kDa protein had good imunogenicity and could serve as a candidate for protective antigen of L.interrogans and the inserted fragment of pDL121 could be a new gene .

AIM: To study the recombinant plasmid pDL121 and its expression product in E.coli. METHODS: pDL121 was analysed by using 6 different restriction endonucleases and dot blotting, and the isolated 23 kDa protein band was cut and injected twice into rabbits to raise anti - 23 kDa serum. RESULTS: The restriction map of pDL121 was quite different from other leptospiral genes reported and digoxin labeled recombinant DNA probe of pDL121 could detect the pathogenic leptospires, whereas, not the nonpathogenic leptospires. The anti - 23 kDa serum could recognize the sonicated antigen of L. interrogans serovar lai strain 017 and 23 kDa protein expressed in pDL121 and the titer of the antiserum were very high, approximately 1/12 800. Injection of the E. coli lysate of pDL121 with Freund's adjuvant into guinea pigs resulted in some protection of the animal against the challenge with strain 017. CONCLUSION: It indicated that 23 kDa protein had good imunogenicity and could serve as a candidate for protective antigen of L. interrogans and the inserted fragment of pDL121 could be a new gene .