Oral administration: 40 drops of paratropin should be dissolved in a glass of water and administered orally.

The brains from SD rats were removed following decapitation, dissected free of membranes, and the cerebella discarded. Tissues were then homogenized with a Brinkmann Polytron in 20 vol of ice cold Tris-HCl buffer (50 mM, pH 7.7). The homogenates were centrifuged at 40000 × g for 10 min at 4°C and the pellets resuspended in the buffer at a concentration of 50 mg wet weight/ml. Radioligand displacement binding studies were performed using 0.06 nM of [3H]QNB and 0.2-0.4 mg protein. The Kd value for [3H]QNB was previously determined in our laboratory to be 0.1 nM. Analysis of the results was performed as described above. Methylhomatropine displaces radioligand with Ki of 350 nM.