Table 1.

Characteristics of lumbosacral spinal dorsal horn neurons excited by urinary bladder distension (UBD) in intact, female rats

Group		N	Class 1	Class 2/WDR	Class 3/NS	RF Size (l:m:s)
NFS	Total	44
	Type I	22	0	20	2	0:11:11
	Type II	22	0	7	15	9:13:0
AFS	Total	46
	Type I	19	0	16	3	0:11:8
	Type II	27	0	17	10	11:14:2
CFS	Total	40
	Type I	8	0	7	1	0:3:5
	Type II	32	0	21	11	19:13:0

Rats were exposed to one of three conditions: acute footshock (AFS), chronic footshock (CFS) or to no footshock (NFS). All neurons were excited by a 60 mmHg, 20 sec phasic constant pressure UBD. Neurons were further classified according to the following: (1) by counter-irritation effects: Type I neurons had spontaneous activity inhibited >20% by a non-segmental noxious cutaneous stimulus; Type II neurons were not similarly inhibited; (2) by receptive field (RF): Class 1 neurons were excited only by non-noxious stimuli; Class 2/wide dynamic range (WDR) neurons were excited by both noxious and nonnoxious cutaneous stimuli; Class 3/nociceptive specific (NS) neurons responded only to noxious cutaneous stimuli; and (3) by RF size: large (l – hind quarter or > hind quarter with contralateral input); medium (m – long axis > 4 cm, including part of hind limb but not tail); small (s – long axis < 4 cm).