87

$;ynaptl¢ organizatron of the lubstantia g(datirmsa g]omeruli in the spinal tri9emina| nucleu~ of the adult cat

S. Gob~d, ,1. Neuro:ytol., 3 (.1974) 219-243

A iight and electron microscopical analysis of the substantia gelat'n'~sa (SG) of :he spina! trigeminal nucleus of the adult cat revealed terminal~ of fiftl,, ne,'ve axons, dendrites and axons of SG neurons and dendrites of marginal and m,~gn,:cellular neurons. "I'h~ essential feature of the SG neuropil was a glomerulus con: isti~.g of a centrally-lo:~ted fifth nerve ending which formed axodendritic synapses on two ~inds of dendriti': spines and on dendritic shafts. The dendritic processes of this g. omeru [us were linked by two kinds of dendrddendritic synapses..In ad:lition, srr, a l axon, l ending; forn,ed z:y.odendritic synapses on some spines and shafts, and ~: oaxoni~ synapses on the fifth nerve terminal. These connections were interpreted t,~ ndicme that some S(_', ~l ls are inhibitory interneurons which modify the transrr, is;ion of excitatory inp~lt from fifth nerve endings to projection cells (raarginal and z:lagno- cellular neurons). The fifth nerve endings in the SG are morphologicalb distinc- from V nerve enditxg~ in other parts of the trigeminal brain stem nuclei and are col~sidered to be essential !or the perception of thermal and painful stimuli.

PHARMACC,. .OG,,

Marihuana an :1 pa;r

Shirley K. Hill. R. Schwin, D. W. Goodwin and Barbarz, J. Powcll, J. Pha,-; ~a, ,/.

exp. Ther., 188 (]974) 41'.;-4t8

Marihuana, hashish and other preparation of Can;zabis sati,.'a have been u = ed for centurie.~ to relieve pain. Whether cannabis acmal!y has analgesic prop~rt~=.s, however, has not been studied in man. The authors investigated pain and sensati ~n threshold and pain tolerance in 26 healthy maI, ~. subjecis. Cutaneous electrica! sti:n- ulation was ap;" lied to the subject's fingers and tt resholds were determined befor: a ~d after smoking n:,arih,mna. It was found that marihuana affected threshold k y r~- creasing sen:sit3,,ity to b~th painful and non-painful stimulation and reduci~.g tolerar ce for pain. Altkc, ugh it :s not clear how much of" the marihuana-induced chan:;e~ in threshold and tolerance are the result of altered sensory ~;ensiti~ity and how mv.'h are due to c~z:..ages in response bias, the data cast doubt on the usefulness of marl nu; ~~~

as an analg~:.~,ic drag.

Sites of morphine induced analgesia in the, primate brain" reiat ic, n t~ ~:~i~ pathways,

A. l:erth and T. Yak~h, Brain Res., 80 (1974) 135-140

T.V~,e !ocalization of the action of mort~hiLqe (20 #g doses) ;s.as invesr~g.a,e i ir~