Table 1.

Selected coughing-related parameters and heart rates during increasing doses of (−)nicotine, (+)nicotine, and (−)nicotine after pretreatment with mecamylamine

Dosage (−)NIC	PS Cough, %	EP I Cough, kPa	HR After NIC Admin. Only, beats/min	HR After Pretreatment with MEC and NIC, beats/min	Dosage (+)NIC	HR After (+)Stereoisomere of NIC, beats/min
Saline ia	169 ± 33a	−6.8 ± 1.2a	232 ± 10b,d	187 ± 6		195 ± 8
MEC ia				189 ± 5
NIC 0.1	191 ± 63b	−6.2 ± 0.7	226 ± 10b,d	189 ± 6	(+)NIC 0.1	195 ± 7
NIC 0.33	109 ± 24	−5.2 ± 1.2	227 ± 10b,d	186 ± 5	(+)NIC 0.33	196 ± 10
NIC 1	131 ± 42	−5.3 ± 1.1	231 ± 11b,d	186 ± 6	(+)NIC 1	196 ± 10
NIC 3.3	138 ± 23	−5.5 ± 1.6	220 ± 11a,d	181 ± 6	(+)NIC 3.3	195 ± 9
NIC 10	104 ± 24	−4.8 ± 1.5	205 ± 10	182 ± 5	(+)NIC 10	195 ± 9
NIC 33	51 ± 8	−4.2 ± 1.4	200 ± 10	181 ± 4	(+)NIC 33	188 ± 10
					(+)NIC 100	193 ± 9
					(+)NIC 330	194 ± 10
Recovery	154 ± 31a	−4.9 ± 2.0	236 ± 12c,e

Values are means ± SE. Dosages (in μg/kg) are of (−)nicotine (NIC; n = 5 cats), (+)nicotine [(+)NIC; n = 5 cats], and (−)NIC after pretreatment with mecamylamine (MEC; n = 4 cats). ia, Intra-arterial; PS, amplitudes of parasternal muscle EMG, EP I, inspiratory amplitudes of esophageal pressure; HR, heart rate.

^aP < 0.05,

^bP < 0.01,

^cP < 0.001 vs. 33 μg/kg of NIC.

^dP < 0.05,

^eP < 0.01 vs. 10 μg/kg of NIC.