The effect of diaminopyridines on the activity recorded in the dorsal roots of isolated spinal cord.
1. The diaminopyridines (DAP) increase the activity recorded in the dorsal roots of an isolated hamster spinal cord preparation. 2. The threshold for 3,4 DAP was 3 x 10(-6) M and the maximum effect was 10(-4) M. The threshold for 2,3 DAP was 3 x 10(-4) M and the maximum effect was at 10(-3) M. The threshold for 2,6 DAP was 10(-4) M and its maximum effect was at 3 x 10(-2) M. 3. When compared with the monoamino pyridines (AP) 4 AP was the most effective and the order of potency was 4 AP greater than 3,4 DAP greater than 2,3 DAP greater than 2 AP = 3 AP greater than 2,6 DAP. 4. Treatment with AP increased the activity simultaneously recorded in the dorsal and ventral roots, but whilst that in the dorsal root continued after washing away the amino pyridine, that in the ventral root ceased for a period of time. 5. There are indications that the amino pyridines may differently affect dorsal and ventral interneurones.
al-Zamil
Z M
ZM
Department of Neurophysiology, The Medical School, Boldrewood, Southampton University, UK.
Bagust
J
J
Kerkut
G A
GA
D000631:Aminopyridines / Q000494:pharmacology*; D000818:Animals; D006224:Cricetinae; D004566:Electrodes; D005727:Ganglia, Spinal / Q000187:drug effects*; D066298:In Vitro Techniques; D008647:Mesocricetus; D013116:Spinal Cord / Q000187:drug effects*
D000631:Aminopyridines