Benzodiazepine binding increases in the superficial laminae of the trigeminal subnucleus caudalis following central rhizotomy.

Benzodiazepine (BZ) binding is being studied in the spinal trigeminal nucleus of the cat 3 and 11 days following unilateral retrogasserian rhizotomy using in vitro autoradiography and computer-assisted densitometry. At 3 days following rhizotomy there is an increase in number and decrease in affinity of flunitrazepam binding sites in the superficial laminae of subnucleus caudalis of the spinal trigeminal complex. By 11 days, affinity remains below control values and binding site number shows an insignificant but detectable increase. There is no change in binding site characteristics in deeper laminae at either survival time. The results are discussed in relation to the physiological hyperactivity and synaptic changes which occur following such lesions and to other conditions of deafferentation.