Local Anesthesia

Blood samples of 105 domestic Bactrian camels were collected from villages in China (55), MG (28), KAZA (6), RUS (10), and IRAN (6). Blood samples of four dromedaries were also collected from IRAN. The collections were made during routine veterinary treatments with the guidelines from the Camel Protection Association of Inner Mongolia. An endeavor was made to collect samples from unrelated individuals based on the information provided by the owners and local farmers. We collected 50 ml blood for each camel from the jugular vein after disinfection treatment, placed it in EDTA anticoagulant tubes, and then stored it at −80 °C. Ear skin samples (0.5 cm) of 19 wild Bactrian camels were collected from the Great Gobi-Strictly Protected Area A in MG. The wild Bactrian camels chosen were artificially reared and the research was reviewed and approved by the Great Gobi National Park. Proper surgical procedures were adopted in the collection. Local anesthesia (5% procaine hydrochloride) was applied to the ear and the wound was disinfected with iodophor and sulfonamide powder. The samples were eluted with phosphate-buffered saline solutions, placed in cryotubes and were stored at −80 °C.

AC-coupled recordings were made of the cord dorsum potentials for incoming afferent volleys and the electroneurograms (ENGs: the phrenic nerve; the external intercostal nerve in one cat; when appropriate, see below, the dissected hindlimb nerves as listed above). Intracellular recordings were DC-coupled, but a high gain output channel high pass filtered at 1 Hz was also included. Intracellular recordings were made from antidromically identified motoneurons, using an Axoclamp 2B amplifier (Axon Instruments) in either standard bridge mode, or in discontinuous current clamp (DCC) mode. Microelectrodes (typical impedance 5 MΩ) were filled with 2 M potassium acetate, and contained the local anesthetic derivative QX-314 (50 mm) to block actions potentials, so as to facilitate the study of the size of EPSPs at different membrane potentials. Note that in several of the records illustrated, a few action potentials survived, showing the QX-314 block to be incomplete at those times. DCC mode was used to allow for more accurate measurements of membrane potential despite changes in electrode resistance with injected current. The DCC cycling rate was typically around 3 kHz with optimal capacitance compensation. Most often slow depolarizing and hyperpolarizing ramps of currents were used (triangular current ramps), but some step changes of constant current levels were also employed. During many of the motoneuron recordings we also recorded efferent discharges from the hindlimb nerves via the same electrodes as used for antidromic identification purposes. This was rarely done in the early experiments, where the focus was on the voltage-dependent amplification of synaptic potentials, but once it was realized that a locomotor drive was sometimes present in the recordings, then these electrodes were switched to their recording mode as soon as antidromic identification had been confirmed. The ENG recordings were done with custom built amplifiers and analog filtering (1–10 kHz) and digitized at a rate of 10 kHz. Full wave rectification and additional filtering was done during analysis so that the onset and the offset of ENG bursts in each nerve were identified by visual inspection of ENG levels crossing a baseline defined by no activity periods. These onset and offset points were used during cycle-based averaging of ENG activity. The data were collected and analyzed with a Canadian software-based QNX-system, developed by the Winnipeg Spinal Cord Research Center to run under a real-time Unix personal computer, usually using separate runs of 200 s duration.

Feed intake of sows was recorded daily, and the litter size and live weight of piglets were recorded weekly, from which the milk yield was estimated using the equations developed by Hansen et al. [7 (link)]. On d 10 and d 17 of lactation, both milk samples and mammary biopsies were collected 4 to 5 h after morning feeding, and milk samples were collected first, while the sows were held by snare restraint. The milk samples were collected after ear vein injection of 0.3 mL (10 IU/mL) oxytocin (Løvens Kemiske Fabrik, Ballerup, Denmark). The mammary biopsies were collected from three selected glands using a Manan Pro-Mag 2.2 biopsy gun with a 14-gauge needle (Medical Device Technologies, Gainesville, FL, USA) after washing, wiping with ethanol, and application of local anesthesia according to the method described by Theil et al. [21 (link)]. Approximately 20 mg biopsy was collected, immediately frozen in liquid nitrogen, and then transferred to −80 ℃ to store for later analysis of mRNA expression.