PT  - JOURNAL ARTICLE
AU  - OTTO Z. SELLINGER
AU  - EDWARD F. DOMINO
AU  - VERNON B. HAARSTAD
AU  - MARGARET E. MOHRMAN
TI  - INTRACELLULAR DISTRIBUTION OF C<sup>14</sup>-HEMICHOLINIUM-3 IN THE CANINE CAUDATE NUCLEUS AND HIPPOCAMPUS
DP  - 1969 May 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 63--76
VI  - 167
IP  - 1
4099  - http://jpet.aspetjournals.org/content/167/1/63.short
4100  - http://jpet.aspetjournals.org/content/167/1/63.full
SO  - J Pharmacol Exp Ther1969 May 01; 167
AB  - C14-hemicholinium-3, methyl-labeled (C14-HC-3), was administered intraventricularly to acute dogs. At 30, 60 and 240 min postinjection, its intracellular distribution was determined in the caudate nucleus and hippocampus. Simultaneously the intracellular localization of succinate reductase, glutamine transferase, acetylcholinesterase (AChE) and aryl sulfatase was established and the validity of their use as subcellular markers for caudate and hippocampus was confirmed. Although C14-HC-3 accumulated in the heavy particulate fraction NEML (containing nerve endings, mitochondria and lysosomes) in both brain regions, the rate of its concentration was considerably higher in the caudate. Discontinuous density gradient centrifugation of fraction NEML yielded subfractions A, B, C, D and E. Although AChE showed enrichment in fractions B and C, up to 30% appeared in fraction D, which also exhibited (in the caudate) the highest relative specific concentration of C14-HC-3. Centrifugation of caudate fractions C and D in continuous density gradients confirmed the association of AChE and of C14-HC-3 with, and the real density difference between, the two granule populations comprising the fractions C and D. Experiments designed to assess the extent of the association of C14-HC-3 with nerveending membranes revealed that approximately 11% of the total NEML-associated C14-HC-3 resists attempts at extrusion and/or solubilization and, hence, denotes tightly bound C14-HC-3. The findings are interpreted to indicate that the majority of fraction C nerve endings contain few mitochondria, have a low affinity for HC-3 and exhibit high levels of AChE, while those of fraction D have most of the mitochondria-filled nerve endings, 30% of the AChE and a high affinity for HC-3. It is suggested that there are two populations of cholinergic nerve endings in the caudate nucleus. © 1969, by The Williams & Wilkins Company